Icing in Alaska

International Wind-Diesel Workshop Mar. 11, 2011

Rich Stromberg / rstromberg@aidea.org

Tom Ainsworth NWS

Tom Ainsw

orth NW

S

Tom

Ainsworth N

WS

Photo: R. Hafner/WCE

Atqasuk Hoar Frost – Light Rime

Photo: D. Vaught/V3

“Data recovery in Atqasuk was marginal with 63 to 73 percent data return from the anemometers and wind vane. The missing data represents the windier winter months when data recovery was extremely poor. This poor data recovery was due to soft rime ice (hoarfrost), beginning in October and lasting to early May.”

Newton Peak Rime Ice

Nome Region Wind Model – 50m AGL

Warm/moist air off the coast can cool as it rises over inland hills/mountains

Newton Peak Met Tower

Newton Peak Met Tower

Newton Peak Rime Ice

Newton Peak Rime Ice

Newton Peak Rime Ice

Newton Peak Tower Collapse

Newton Peak Rime Ice

Photo: R. Hafner/WCE

Newton Peak Rime Ice

Newton Peak Rime Ice

Photo: R. Hafner/WCE

Icing Summary• Super-cooled liquid exists in a cloud well below 0 deg

C.• Meteorological studies are essential prior to wind

development.• Presence of icing/ice-free sites is not an “either/or”

state, rather a gradient.• Find the balance between better wind regimes vs. icing

losses.• Very site specific based on terrain, predominant wind

directions and presence of moist air masses.• Some icing can impact turbine output and even affect

turbine survivability.