Weekly Cat Report April 17, 2020

Weekly Cat Report 2

This Week’s Natural Disaster Events

Event Impacted Areas Fatalities Damaged Structures and/or Filed Claims

Preliminary Economic Loss (USD)* Page

Severe Weather United States 38+ Tens of Thousands+ 1+ billion 3 Flooding Papua New Guinea 10 Unknown Thousands 15 Flooding Indonesia 0 7,500 Unknown 15 Flooding Vietnam 0 716 1.7+ million 15

*Please note that these estimates are preliminary and subject to change. In some instances, initial estimates may be significantly adjusted as losses develop over time. This data is provided as an initial view of the potential financial impact from a recently completed or ongoing event based on early available assessments.

Along with this report, we continue to welcome users to access current and historical natural catastrophe data and event analysis on Impact Forecasting’s Catastrophe Insight website: http://catastropheinsight.aon.com

Weekly Cat Report 3

Major tornado outbreak sweeps the U.S. Southeast A prolific severe weather outbreak swept across parts of the southern and eastern United States from April 10-14, killing at least 38 people and injuring hundreds of others. The outbreak prompted a minimum of 121 confirmed tornado touchdowns from Texas to Maryland in addition to very large hail, damaging straight-line winds, and torrential rains that prompted flash flooding in the Tennessee Valley. Among the hardest-hit areas came in Mississippi, Alabama, Louisiana, Georgia, Tennessee, South Carolina, and North Carolina following deadly tornadoes, large hail, and non-tornadic synoptic winds topping 70 mph (110 kph). Total economic and insured losses were expected to minimally reach into the hundreds of millions (USD); though likely to approach or surpass USD1 billion. This is expected to be the fifth billion-dollar severe convective storm event in the U.S. thus far in 2020.

Meteorological Recap Various branches of NOAA – including the Storm Prediction Center (SPC), National Weather Service (NWS), and the Weather Prediction Center (WPC) – began forecasting the potential for a multi-day severe weather outbreak as early as April 8. Most of the forecast model guidance was consistent in the development of a surface cyclone interacting with a broader upper-level area of low pressure, a vigorous jet stream, wind shear (critical for spin to initiate tornadogenesis), and very warm and moist air surging out of an anomalously warm Gulf of Mexico.

April 10 The primary driver of much of the severe weather surrounded an upper level area of low pressure that initially meandered out of Southern California into the Desert Southwest on April 10. This low helped create a surge of low-level moisture that streamed out of the Pacific Ocean into parts of West Texas. This moisture, combined with a strong low-level jet, strong mid-level veering winds, and steep lapse rates, set the stage for afternoon and evening severe thunderstorms. As anticipated, the storms prompted very large hail across parts of West Texas. Hailstones larger than the size of baseballs affected Crane County, TX; with golf ball-sized hail noted in Upton, Andrews, Crockett, and Ector counties, too.

Weekly Cat Report 4

April 11 Convective activity initially began during the late morning hours on April 11. The storms were initiated by a mid-level area of low pressure that traversed from Arizona towards the Texas Panhandle. As the system moved eastward, a surface area of low pressure began to develop as it was fueled by an abundance of low-level moisture surging out of the Gulf of Mexico. The strengthening of the cyclone was aided by steep lapse rates (temperature difference with height), a potent dry line (a dividing line between dry and moist air), and an active jet stream that destabilized the atmosphere. Such conditions were also favorable for supercell formation that could prompt large hail and the possibility of tornadoes.

The SPC declared a broad Enhanced Risk of severe weather for most of Texas, and an even larger Slight Risk area that stretched into parts of Oklahoma, Arkansas, and Louisiana. A large Tornado Watch was issued for the afternoon and evening hours across north-central Texas as daytime heating did initiate powerful thunderstorms as expected; while a Severe Thunderstorm Watch covered parts of Kansas and Missouri as the leading warm front lifted northward and destabilized the atmosphere into the Midwest.

The storms resulted in numerous individual supercells that tracked across much of north-central Texas and into areas near San Antonio metro, in addition to other powerful storms near the warm front into Kansas, Missouri, and Nebraska. Hail was the predominant sub-peril that occurred as clusters of storms dropped hail the size of softballs in parts of Val Verde and Kinney counties in Texas, and tennis ball or larger in Marion and Pottawatomie counties (Kansas) and Tillman County, Oklahoma. Parts of Missouri and Nebraska also cited notable hail.

Straight-line winds topping 60 mph (95 kph) were noted primarily in central Texas, as the broad cluster of thunderstorms persisted during the overnight hours to daybreak on April 12. These storms would continue to shift eastward across the Southeast.

Weekly Cat Report 5

April 12 Atmospheric conditions became much more concerning for a significant severe weather outbreak on April 12 as a complex weather map emerged. As the initial mid-level low and trough shifted out of the Southern Plains and through the Southeast towards the Appalachian Mountains on April 11 into early on April 12, this set the stage for a new surface area of low pressure to begin rapidly organizing in Oklahoma during the first half of the day. This low was accompanied by very rich low-level moisture from the Gulf of Mexico that lifted northward as a leading warm front across much of the Deep South and towards the Ohio Valley. Morning thunderstorms commenced in the Southeast which only further enhanced, but complicated atmospheric instability by laying numerous “boundaries” that would later combine with the maximum heating of the day to further initiate storms. This also brought some uncertainty as to whether lingering cloud cover could act as a “cap” for storms later in the day.

As daytime heating occurred, this coincided with very powerful mid-level flow and a cross low-level jet that enhanced wind shear and “directional veering with height” which is critical for maximum vorticity that creates “spin” necessary for tornadogenesis. Such conditions suggested the probability of long-tracked tornadoes that would be on the ground for an extended period. Very steep lapse rates – which means much colder air not far from the surface; thus allowing the potential of large hail hitting the surface due to a lack of time to melt while falling to the surface – suggested a large hail threat extending from Oklahoma into Alabama. The fast-moving mid-level wind flow also increased the probability of damaging straight-line winds and “spin-up tornadoes” into the Alabama, Tennessee, and Georgia as supercells were likely to coalesce into a linear cluster during the overnight hours into April 13 as maximum heating waned.

The significance of the forecast conditions prompted the SPC to initially declare a Moderate Risk of severe weather three days in advance. This risk level – which is Level 4 out of a 5-tiered scale – was just the 17th time since 2003 for such an early advanced warning to be initiated. On April 12, the SPC did maintain a Moderate Risk (Level 4) for much of the Southeast, as the spatial coverage included parts of Arkansas, Louisiana, Mississippi, Alabama, and Georgia (including Atlanta). Even larger Enhanced (Level 3) and Slight (Level 2) risk areas stretched from Texas to Florida to Ohio. The risk prompted multiple Particularly Dangerous Situation (PDS) Tornado Watches in Louisiana, Arkansas, Mississippi, Alabama, and Tennessee.

As noted previously, morning thunderstorms exiting from Texas and Arkansas pushed eastward across the Southeast. A large cluster of storms brought heavy rainfall and caused some hail and wind damage, including tornadoes in Texas and Louisiana (such as a confirmed EF3 tornado to the city of Monroe, LA, where a Tornado Emergency was declared in Ouachita Parish). These storms set the stage for a substantial outbreak later in the day.

April 12 Surface Map (Source: NOAA)

Weekly Cat Report 6

By the late afternoon hours, the noted mid-level trough and surface cyclone really began to organize, activity began to rapidly accelerate from Louisiana into Mississippi. Dozens of individual thunderstorms – including several which became powerful and dangerous supercells – developed in a secondary wave ahead of the leading cold front and embedded within the low-level moisture flow tracking from southwest to northeast.

Two supercells led to catastrophic effects in Mississippi. An initial cell would produce a long-tracked tornado that showed exceptional wind speeds on Doppler radar, and was so strong and violent that incurred damage along the storm’s path – which tracked through Walthall, Lawrence, Marion, and Jefferson Davis counties – was noted more than 20,000 feet (6,096 meters) into the atmosphere and sprayed well beyond the rear flank of the cell itself. This only occurs in the strongest tornadoes and many meteorologists compared the radar imagery to the infamous EF5 tornado in El Reno, Oklahoma on May 24, 2011. As the event unfolded, the SPC sent a very rare Mesoscale Discussion noting “a violent tornado with potential peak winds of 170 to 205 mph is likely ongoing … this is an exceptionally rare event”. An official NWS survey concluded that this tornado at its peak was an EF4 with up to 170 mph (275 kph) winds along its nearly 70-mile (110-kilometer) path. At its peak, the twister had an enormous maximum width of 2.0 miles (3.2 kilometers) wide. At least four people were killed, and dozens of others were injured.

Just minutes later, a second supercell took a nearly identical path across southern Mississippi. This storm was another long-tracked event that moved through parts of Jefferson Davis, Covington, Jones, Jasper, and Clarke counties. NWS meteorologists confirmed that the twister had up to 130 mph (210 kph) winds at its peak; an EF3. At least two fatalities were attributed to this tornado.

A Tornado Emergency was declared for each of the violent twisters in Mississippi. The small town of Soso was simultaneously under a Tornado Emergency for both supercells at the same time.

Other significant tornadic events occurred across Louisiana, Mississippi, Alabama, Tennessee, and Georgia on April 12 as multiple waves of storms continued to generate in the extremely amplified atmosphere into the late evening and overnight hours into April 13. A third Tornado Emergency was declared just east of Chattanooga, Tennessee as another distinct supercell produced a “debris ball” on Doppler radar; signifying intense winds and major damage.

The numerous individual thunderstorm cells began to coalesce into a single, linear cluster while in Alabama as straight-line winds gusting beyond 70 mph (110 kph) was cited as it also extended into Georgia and later the Carolinas. Additional tornadoes also touched down in the greater Atlanta, Georgia metro area. Several inches of excessive rainfall were also recorded in the Southeast that led to flash flooding.

Weekly Cat Report 7

At the same time, another line of storms developed along the primary cold front itself as additional reports of hail and non-tornadic winds swept across Oklahoma, Texas, Arkansas, and Louisiana before moving into Mississippi, Alabama, and Tennessee. Some areas in the Deep South were affected by no fewer than four separate rounds of thunderstorms on April 12.

Total breakout of April 12 tornadoes: EF0 (9), EF1 (36), EF2 (15), EF3 (3), EF4 (2), EF5 (0)

April 13 While atmospheric conditions were not as amplified for as severe an event on April 13, it was still highly conducive for widespread thunderstorm activity from the Mid-Atlantic southward to Florida. Most of the dynamics weakened as the primary surface cyclone further shifted towards the Midwest. However, very moist air and a strong low-level jet brought above normal temperatures and high dewpoints that made the atmosphere highly capable of producing and sustaining severe events.

Early morning, pre-frontal thunderstorms were first observed in parts of Florida, Georgia, and the Carolinas. This was the cluster of convection that led to many damaging straight-line wind and sporadic tornado reports elsewhere in the Southeast. These morning storms became more intense as they entered a heat and moisture-rich environment from the Florida Panhandle into the Mid-Atlantic. The SPC noted the probability of embedded supercells given the destabilized atmosphere. Given these conditions, the SPC declared a large Enhanced Risk of severe weather that stretched from northern Virginia to southeast Georgia; and an even broader Slight Risk that extended from Pennsylvania to the Florida Panhandle. The greatest risk included impacts from damaging straight-line winds and possible tornadoes.

As the day unfolded, the event played out as anticipated. Early morning storms that ejected out of Georgia and Tennessee began to emerge into the Carolinas. Overnight warmth and a highly juiced atmosphere aided in the continued intensity of the main line. There were many embedded supercells within the elongated cluster that stretched from Virginia to the Florida Panhandle; which prompted numerous tornado warnings – including a Tornado Emergency in Walterboro, South Carolina. Several other tornado warnings were issued as confirmed touchdowns were cited in North Carolina and elsewhere in South Carolina. The fast-moving nature of the storm cluster resulted in many “spin-up” twisters as atmospheric rotation remained highly prevalent.

Beyond the tornadic and straight-line wind damage, extremely gusty synoptic-induced winds occurred across much of the Great Lakes and Northeast on April 13. With much colder air sinking southward out of Canada behind another cold front pushing through the Midwest and Plains – plus interacting with an additional surface low in the Great Lakes – this established a tight pressure gradient that subsequently prompted very high wind gusts across much of the Eastern U.S. Winds topping 70 mph (110 kph) were recorded as the winds added further damage impact to several states.

Total breakout of April 13 tornadoes: EF0 (15), EF1 (26), EF2 (7), EF3 (7), EF4 (0), EF5 (0)

Weekly Cat Report 8

Tornado Tracks: April 10-14 The graphics below highlight all 121 confirmed tornado tracks from the event – preliminary totals via National Weather Service (NWS) assessments. The second graphic highlights the number of tornadoes per state and compares the outbreak against the entire monthly April average of tornadoes in the Doppler era (1990-2018).

Weekly Cat Report 9

Miscellaneous April is one of the most active months for tornadoes in the United States. The month has recorded some of the most prolific and historic outbreaks on record in the country, including April 3-4, 1974 and April 26-27, 2011.

Also, the United States remained in one of its longest stretches between F/EF5 tornado touchdowns in the modern record. As of April 17, it marked 2,524 days between events; the last occurring on May 20, 2013 in Moore, Oklahoma. Only a stretch of 2,923 days from May 3, 1999 to May 4, 2007 was longer.

Weekly Cat Report 10

Event Details The broad storm system resulted in widespread and substantial damage across nearly two-dozen states, and in some cases where tornadoes were the most intense, the damage impacts were catastrophic. At least 38 people were killed, and hundreds of others were injured during the outbreak. This was the deadliest U.S. tornado outbreak since March 2-3, 2012. The scale of damage was driven by tornado touchdowns, hail approaching the size of softballs, and straight-line winds topping 80 mph (130 kph). Torrential, extended rainfall additionally led to flash flooding; while synoptic winds topping 70 mph (110 kph) led to impacts in the Great Lakes and Northeast. More than 1.8 million customers were without power during the peak of the event. States of emergency were declared in Louisiana, Mississippi, Alabama, Georgia, and South Carolina.

Tornado Mississippi

The most catastrophic damage was incurred in Mississippi as nearly a dozen tornadoes touched down across the state. A statewide state of emergency was declared. Emergency management agencies in Walthall, Lawrence, Marion, Jefferson Davis, Covington, Jones, Jasper, and Clarke counties noted that hundreds of homes and other structures were damaged or destroyed. Catastrophic damage in association with two violent long-tracked tornadoes led to extensive impacts in the towns of Bassfield, Seminary, Soso, Heidelberg, Prentiss, Laurel, Collins, Vossburg, and Enterprise. The scope of damage included single-family homes, apartment complexes, businesses, and other outbuildings.

The most intense tornado was rated an EF4 with at least 170 mph (275 kph) winds that touched down in Jefferson Davis County and tracked 67.77 miles (109.06 kilometers) before lifting in Clarke County. At its peak, the twister had an enormous maximum width of 2.0 miles (3.2 kilometers) wide; one of the widest tornadoes ever observed on record. At least four fatalities were directly attributed to this tornado, which caused exceptional damage to structures in Jefferson Davis, Covington, Jones, Jasper, and Clarke counties. In some cases, the extreme tornadic winds completely wiped away single-family homes down to their concrete slabs and snapped healthy trees in two. This only happens in the most intense tornado events.

The second “twin” tornado struck just minutes later and took a nearly identical path. That tornado was confirmed with at least EF3-intensity winds as it touched down in Lawrence County and tracked a remarkable 82.61 miles (132.95 miles) before lifting in Jasper County. Multiple fatalities and dozens of injuries occurred. The vortex had a base of at least 1.0-mile (1.6-kilometers) wide at its peak.

Some debris from these twisters were recorded nearly 40 miles (64 kilometers) away in Alabama.

Tornado near Soso, MS (Source: @ConnorWx)

Weekly Cat Report 11

Further tornado damage was also cited in Yazoo City and other cities located in northern sections of Mississippi. A second EF4 tornado with 170 mph (275 kph) winds touched down in Walthall County, caused extensive damage, and killed one person. There were 12 confirmed fatalities across the state.

In total, the Mississippi Emergency Management Agency (MEMA) estimates that 1,206 homes were impacted by this event. Of these, 352 were in Covington County, 328 in Jones County, and 205 in Jefferson Davis County.

Louisiana Several confirmed tornadoes also swept across Louisiana. The most significant occurred in the city of Monroe, where officials cited roughly 300 homes that were damaged or destroyed. The tornado also led to extensive damage at Monroe Regional Airport as several planes and a hangar were severely damaged. Airport officials cited the damage to planes alone was expected to approach USD30 million.

Another impactful twister in Ouachita Parish was noted in the Cherry Blossom region located just north of Millhaven. Dozens of homes and some commercial structures were damaged or destroyed on both sides of Interstate 20. Pecanland Mall was also affected. No one was killed, though several people were injured.

In total, Ouachita Parish Office of Homeland Security and Emergency Preparedness (OHSEP) estimated that a total of 458 homes were impacted by three tornadoes, of which 23 were destroyed, 108 had major damage, 243 had minor damage, and another 84 were affected to varying degrees. Dozens of additional structures (including businesses) were also severely damaged.

State officials cited additional widespread damage in Bossier and DeSoto Parishes.

Tornado damage in Monroe, LA (Source: City of Monroe, LA)

Weekly Cat Report 12

Tennessee Tornadoes left a wide swath of damage across southern section of the state late on April 12 into early April 13. At least 20 people were hospitalized. One tornado near Chattanooga damaged or destroyed more than 150 homes and commercial structures. Some of the hardest-hit areas included in East Brainerd and East Ridge in Hamilton County. The damage was significant as debris was detected in real-time in Doppler radar as the tornado tracked through. An NWS damage survey indicated that tornado was an EF3 with up to 145 mph (235 kph) winds. Further tornado damage was noted in neighboring Bradley County, where six people were hospitalized following extensive damage to homes.

Georgia At least seven confirmed fatalities were cited in Murray County, Georgia following a tornado that tracked through two mobile home parks. Twenty-three other people were injured. This same tornado would later shift northeastward into Tennessee and lifted in Polk County (TN).

Additional tornadic winds blew a home in Upton County off of its foundation and onto the middle of State Highway 74. Such an occurrence likely highlighted a poorly anchored foundation, but did however, reinforce the intensity of winds. In total, 159 structures were impacted by this tornado, 38 with minor damage, 20 with major damage, and 7 were reported destroyed. Further tornado damage was cited across Chattooga, Dade, Fulton, and Putnam counties. One tornado narrowly missed Atlanta’s Hartsfield Airport.

South Carolina Tornadoes associated with the main line of storms on April 13 led to additional fatalities in South Carolina. At least five people died in tornado-related incidents in Hampton County after a tornado caused major damage to a mobile home community near Nixville. A separate tornado left two dead and seven people injured in Orangeburg County near the city of Livingstone. The tornado was rated EF3 with up to 140 mph (220 kph) winds as it destroyed several mobile homes. Other confirmed tornadoes were noted in Colleton County (where another person was killed). Extensive damage to homes and more than a dozen airplanes at the Lowcountry Regional Airport were also noted in the town of Walterboro. Of particular note, two tornadoes just south of the city of Columbia were engaged in a Binary/Fujiwhara interaction which involved the vortexes rotating – or “dancing” – around each other. This is a rare phenomenon for tornadoes and is perhaps more often seen with tropical cyclones.

Another tornado that produced a 114 mph (183 kph) wind gust was recorded in Murrells Inlet, though winds topping 80 mph (130 kph) were also cited a mile away in Garden City. Tornadoes were confirmed in Oconee, Greenville, and Aiken counties. The Oconee tornado – which also tracked into Pickens County along its 16.66-mile (26.81-kilometer) path – was rated an EF3 with up to 160 mph (260 kph) winds. At its peak, the twister had at least a 0.5-mile (0.8-kilometer) width. The EF3 tornadoes were the first in South Carolina since April 2009, and the first time since March 15, 2008 with more than one such event on the same day.

Tornado damage in Upton County, GA (Source: @WXMolly)

Damage at an auto plant in Seneca, SC (Source: tiremeetsroad.com)

Weekly Cat Report 13

As of this writing, the South Carolina Emergency Management Division (SCEMD) estimates that 911 homes were impacted, of which 111 were destroyed, and 181 sustained major damage. In total, nine storm related fatalities have been confimred.

North Carolina Tornado damage was also noted across central and eastern North Carolina. Damage impacts were cited in Alamence, Columbus, Onslow, and Pender counties. This included a high volume of homes (single-family and mobile), businesses, and farming structures being affected; along with wide swaths of trees. Most of the tornadoes in the state were rated EF0 or EF1. Perhaps most notable was an EF1 that destroyed several outbuildings in Pender County and also damaged Pender Fire Station #21.

Alabama No fewer than 26 tornadoes were confirmed in Alabama – notably in Cullman, Walker, Jefferson, Marshall, Blount, and Dekalb counties – as damage was extensive in some instances. Hundreds of properties sustained major wind damage as tornadoes ripped off roofs and led to extensive impacts. Downed trees from tornadic winds led to further damage. At least five people were injured due to tornadoes, with most of the injuries cited near the town of Dora as people were in their vehicles. The two strongest and most notable events included an EF2 that initially touched down in Marshall County before crossing into Dekalb, and another EF2 that tracked across Cullman County.

Other States The fast-moving nature of thunderstorms – and the accompaniment of powerful winds bowing outwards during its eastward progression – further resulted in quick spin-up tornadoes in parts of the Florida Panhandle and elsewhere in the Mid-Atlantic. Suspected twisters were also noted in parts of Virginia, Maryland, Pennsylvania, and Delaware as tornado warnings were issued.

Straight-Line Wind Substantial non-tornadic winds were additionally recorded throughout the Southeast, Mid-Atlantic, and Northeast. Multiple fatalities were incurred due to downed trees onto properties that struck residents who were sleeping in their homes. Nearly 500 reports of straight-line winds were reported into the SPC throughout the lifespan of the event. Most of the gusts included winds between 50 and 60 mph (80 and 95 kph), though some areas cited powerful downdrafts that topped 90 mph (145 kph). This resulted in extensive damage to properties as trees and powerlines were downed across nearly 20 states.

On April 13, a microburst in Marlboro County, South Carolina produced estimated maximum wind speeds between 100-110 mph (160-180 kph) causing damage near Wallace, where several homes were impacted, and an unanchored mobile home was flipped from its foundation.

Weekly Cat Report 14

Large Hail & Flash Flooding The biggest initial driver of damage during the event from April 10-12 was large hail. Hail the size of softballs was noted in parts of Texas, where damage was particularly impactful in the town of Del Rio in Val Verde County. Hail approaching the size of golf balls and limes were further reported across the Texas Panhandle and southern Oklahoma. Baseball-sized hail was also noted in Kansas and Nebraska. Damage was extensive in the greater Lincoln, NE metro area as large hail punctured holes in roofs of properties, and/or caused denting or siding impacts to structures and vehicles.

The event was also marked by torrential rainfall that resulted in several rounds of thunderstorms tracking across the same areas of the Southeast and Tennessee Valley. Seventy-two-hour rain totals topped 6.00 inches (152.4 millimeters) in parts of Mississippi, Alabama, and Tennessee that resulted in instances of flash flooding. Several rivers overflowed their banks and left nearly 100 roads closed in Tennessee, and there were reports of property inundation. One person was killed after being swept away by floodwaters at a bridge in the town of Kimball. Four bridges in total were damaged.

Similar damage was incurred in Dekalb County, Alabama after Big Wills Creek overflowed its banks and inundated dozens of businesses in Collinsville and Fort Payne. Major floods were also noted in the Alabama counties of Jackson, Madison, and Morgan.

Synoptic Wind Major non-convective wind damage was also cited across parts of the Northeast, Mid-Atlantic, and Great Lakes. With the main area of low pressure beginning to strengthen as it shifted east-northeastward, it interacted with ridging to its west and north to create a tight pressure gradient. Such conditions resulted in winds gusting beyond 60 mph (95 kph), and in some cases higher than 70 mph (110 kph), from Michigan to Maine. This led to many reports of downed trees and powerlines. Hundreds of thousands of power outages were recorded due to these winds.

Financial Loss Given the extensive damage footprint across much of the Southern and Eastern U.S. – which included catastrophic effects from tornado touchdowns, large hail, straight-line winds, and flash flooding – it is anticipated that the financial toll will be significant. A preliminary view suggests economic and insured losses minimally reaching into the hundreds of millions (USD); though it was highly likely that the overall economic toll will exceed USD1 billion. This is expected to become the fifth billion-dollar U.S. severe convective storm event thus far in 2020, and the second in two weeks.

Weekly Cat Report 15

Natural Catastrophes: In Brief Flooding (Vietnam) Torrential rains coupled with thunderstorms, tornadoes, and hail occurred in Vietnam on April 10-12, causing multiple injuries and disruptions in several provinces. According to the Standing Office of the Central Committee for Natural Disaster Prevention and Control, more than 716 houses were damaged or destroyed in Son La, Lao Cai, and Lai Chau provinces. The events continued an active stretch from March 10-12 that affected agriculture, livestock, and disrupted traffic movements. Total economic damages were minimally estimated at VND40 billion (USD1.71 million).

Flooding (Papua New Guinea) Heavy rains prompted flash flooding and landslides in Papua New Guinea’s Kundiawa-Gembogl District, Chimbu Provinces on April 10. The worst damage was noted in Kegesuglo where a landslide damaged or destroyed multiple homes, along with fish and poultry farms. Government officials noted that at least 10 people had died in the Kegesuglo area. Total economic losses were likely in the thousands (USD).

Flooding (Indonesia) Heavy rains swept across Lamongan Regency of East Java, Indonesia, since April 9, resulting in flash flooding in several districts. According to the local disaster authorities and news agencies, around 7,500 houses were flooded, and at least 25,000 people were displaced from several districts of the Lamongan Regency.

Weekly Cat Report 16

Global Temperature Anomaly Forecast

Source: Climate Reanalyzer, Climate Change Institute, University of Maine, USA

Weekly Cat Report 17

Global Precipitation Forecast

Source: Climate Reanalyzer, Climate Change Institute, University of Maine, USA

Weekly Cat Report 18

Weekly Sea Surface Temperature (SST) Anomalies (°C)

The SST anomalies are produced by subtracting the long-term mean SST (for that location in that time of year) from the current value. This product with a spatial resolution of 0.5 degree (50 kilometers) is based on NOAA/NESDIS operational daily global 5 kilometer Geo-polar Blended Night-only SST Analysis. The analysis uses satellite data produced by AVHRR radiometer.

Select Current Global SSTs and Anomalies Location of Buoy Temp (°C) Departure from Last Year (°C) Eastern Pacific Ocean (1,020 miles SW of San Salvador, El Salvador) 26.85 +3.37 Niño3.4 region (2°N latitude, 155°W longitude) 26.83 +0.55 Western Pacific Ocean (700 miles NNW of Honiara, Solomon Islands) 30.32 +0.50

Sources: ESRL, NOAA, NEIS, National Data Buoy Center

Weekly Cat Report 19

El Niño-Southern Oscillation (ENSO) ENSO-neutral conditions are currently present. NOAA notes that there is a roughly 65 percent chance of neutral conditions lingering through the Northern Hemisphere (boreal) spring months, and a 55 percent chance of lasting through the summer months.

El Niño refers to the above-average sea-surface temperatures (+0.5°C) that periodically develop across the east-central equatorial Pacific. It represents the warm phase of the ENSO cycle. La Niña refers to the periodic cooling of sea-surface temperatures (-0.5°C) across the east-central equatorial Pacific. It represents the cold phase of the ENSO cycle.

El Niño and La Niña episodes typically last nine to 12 months, but some prolonged events may last for years. While their frequency can be quite irregular, El Niño and La Niña events occur on average every two to seven years. Typically, El Niño occurs more frequently than La Niña.

ENSO-neutral refers to those periods when neither El Niño nor La Niña conditions are present. These periods often coincide with the transition between El Niño and La Niña events. During ENSO-neutral periods the ocean temperatures, tropical rainfall patterns, and atmospheric winds over the equatorial Pacific Ocean are near the long-term average.

El Niño (La Niña) is a phenomenon in the equatorial Pacific Ocean characterized by a five consecutive 3-month running mean of sea surface temperature (SST) anomalies in the Niño 3.4 region that is above the threshold of +0.5°C (-0.5°C). This standard of measure is known as the Oceanic Niño Index (ONI).

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Source: NOAA

Weekly Cat Report 20

Global Tropics Outlook

Source: Climate Prediction Center

Weekly Cat Report 21

Current Tropical Systems

Location and Intensity Information Name* Location Winds Storm Reference from Land Motion**

* TD = Tropical Depression, TS = Tropical Storm, HU = Hurricane, TY = Typhoon, STY = Super Typhoon, CY = Cyclone ** N = North, S = South, E = East, W = West, NW = Northwest, NE = Northeast, SE = Southeast, SW = Southwest Sources: National Hurricane Center, Joint Typhoon Warning Center, Central Pacific Hurricane Center

Weekly Cat Report 22

Global Earthquake Activity (≥M4.0): April 10-16

Significant EQ Location and Magnitude (≥M6.0) Information Date UTC) Location Magnitude Depth Epicenter 4/12/20 36.96S, 77.45E 6.1 10 km 96 kilometers (60 miles) N of Amsterdam Island, France 4/14/20 30.39S, 176.35W 6.0 31 km 19 kilometers (12 miles) SE of Raoul Island, New Zealand 4/16/20 16.93N, 85.71W 6.0 10 km 55 kilometers (34 miles) NNE of Savannah Bight, Honduras

Source: United States Geological Survey

Weekly Cat Report 23

U.S. Weather Threat Outlook

Potential Threats The most significant threat will be the potential for severe weather and heavy rains across the

Southern Plains and Deep South late this weekend. Many of these areas are already dealing with saturated soils and recovering from recent severe weather and flooding. Heavy rains will later spread across the rest of the Southeast by Monday morning.

A second system is expected to bring heavy rain and thunderstorms to the Southern Plains, Southeast, and into the Mid-Atlantic beginning mid-week.

Drought conditions persist across regions of Southern Texas, the Plains, and the Pacific Northwest.

Ongoing flooding concerns remain for portions of the Upper Midwest and Mississippi River Valley due to prolonged elevated precipitation and oversaturated soils. Source: Climate Prediction Center

Weekly Cat Report 24

U.S. Wildfire: Significant Fire Risk Outlook & Activity

The National Interagency Fire Center has highlighted an extended risk of elevated wildfire conditions across parts of the Desert Southwest, Plains, and the Southeast through the second week of April. One area of focus will be in the Desert Southwest as dry and windy conditions establish that enhances the fire risk.

Annual YTD Wildfire Comparison: April 10* Year Number of Fires Acres Burned Acres Burned Per Fire 2016 11,122 832,755 74.87 2017 15,692 2,179,375 138.88 2018 13,145 540,164 41.09 2019 7,602 182,747 24.04 2020 8,275 191,665 23.16 10-Year Average (2010-2019) 12,610 548,490 43.50

*Last available update from NIFC; 2020 YTD is from April 2 Source: National Interagency Fire Center Top 5 Most Acres Burned by State: April 16

State Number of Fires Acres Burned Acres Burned Per Fire Oklahoma 491 70,744 144.08 Kansas 31 21,354 688.84 Texas 763 21,285 27.90 Florida 928 20,103 21.66 Mississippi 290 14,949 51.55

Source: National Interagency Fire Center

Weekly Cat Report 25

Current U.S. Streamflow Status

A ≥99th percentile indicates that estimated streamflow is greater than the 99th percentile for all days of the year. This methodology also applies for the other two categories. A steam in a state of severe drought has 7-day average streamflow of less than or equal to the 5th percentile for this day of the year. Moderate drought indicates that estimated 7-day streamflow is between the 6th and 9th percentile for this day of the year and ‘below normal’ state is between 10th and 24th percentile.

Top 5 Rivers Currently Nearing or Exceeding Flood Stage Location Flood Stage (ft) Current Stage (ft) % of Full Capacity Yukon River at Eagle, Alaska 34.00 59.71 176% Red River of The North at Grand Forks, North Dakota 28.00 42.21 151% Lower Atchafalaya River at Morgan City, Louisiana 6.00 8.79 147% Red River of The North at Oslo, Minnesota 26.00 37.29 143% James River at Columbia, South Dakota 13.00 18.38 141%

Source: United States Geological Survey

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Source Information Major tornado outbreak sweeps the U.S. Southeast Storms tear through South amid pandemic; more than 30 dead, The Associated Press ‘Everything’s gone’: Tornadoes rip U.S. South, kill at least 26, Reuters A storm system that spawned tornadoes and killed 31 people is taking aim at the East Coast, CNN Violent storms, tornadoes shift to East Coast after leaving at least 30 dead, 1.3 million without power, Washington Post U.S. Storm Prediction Center U.S. National Weather Service U.S. Weather Prediction Center Natural Catastrophes: In Brief Indonesia – Thousands Affected by Floods in Lamongan, East Java, Floodlist Vietnam-Standing Office of the Central Committee for Natural Disaster Prevention and Control Reliefweb

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Contact Information Steve Bowen Director & Meteorologist Head of Catastrophe Insight Impact Forecasting Aon steven.bowen@aon.com Michal Lörinc Senior Catastrophe Analyst Impact Forecasting Aon michal.lorinc@aon.com

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