Snow Depth Property with potentially largest variation in space.
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Transcript of Snow Depth Property with potentially largest variation in space.
Snow Depth
• Property with potentially largest variation in space
Snow Depth
• Property with potentially largest variation in space
• Measure vertical to earth’s surface
Snow Depth
• Property with potentially largest variation in space
• Measure vertical to earth’s surface
Snow Depth
• Property with potentially largest variation in space
• Measure vertical to earth’s surface
Snow Depth
• Property with potentially largest variation in space
• Measure vertical to earth’s surface
SWE measurement
• Mass of water over a unit area – Weigh cylindrical snow sample
• Typically the Mt. Rose or Federal Sampler is used
• A gravimetric technique
SWE measurement
1. Clean the snow tube of debris, snow, etc.
cutter/teeth
snow tube
SWE measurement
1. Clean the snow tube 2. Tare the snow tube
scale
snow tube
cutter/teeth
SWE measurement
1. Clean the snow tube 2. Tare the snow tube
scale
snow tube
SWE measurement
1. Clean the snow tube 2. Tare the snow tube3. Insert tube vertically
SWE measurement
1. Clean the snow tube 2. Tare the snow tube3. Insert tube vertically4. Rotate tube into snowpack
SWE measurement
1. Clean the snow tube 2. Tare the snow tube3. Insert tube vertically4. Rotate tube into snowpack5. Twist sharply at bottom
1. Clean the snow tube 2. Tare the snow tube3. Insert tube perpendicular4. Rotate tube into snowpack5. Twist sharply at bottom6. Pull out vertically
SWE measurement
1. Clean the snow tube 2. Tare the snow tube3. Insert tube perpendicular4. Rotate tube into snowpack5. Twist sharply at bottom6. Pull out vertically7. If an entire column has been
removed, weigh tube with core
SWE measurement
1. Clean the snow tube 2. Tare the snow tube3. Insert tube perpendicular4. Rotate tube into snowpack5. Twist sharply at bottom6. Pull out vertically7. If an entire column has been
removed, weigh tube with core
SWE measurement
Snowpack Density
• Average density = SWE / depth
Snowpack Density
Stratified densities from snow pits1. Dig a pit to the bottom
2. Include a stairway
3. Cut a straight face along the southern wall
4. Measure total depth
5. From top or bottom, measure densities at 10cm intervals
6. Concurrently measure temperature
Snowpack Density
• Kelly Cutter density sample extracter:
Snowpack Density
• Kelly Cutter density sample extracter:
Snowpack Density
• Kelly Cutter density sample extracter:
Snowpack Density
5. From top or bottom, measure densities at 10cm intervals
– Clean wedge-shaped sample extracter (Kelly cutter)
– Tare sample extracter
– Insert sampler vertically to sample wall with bottom parallel to the ground
– Slide plate along open side of sampler
– Pull sampler and plate from wall
– Remove excess snow from bottom and side of sampler
– Weigh sampler and sample
– Density = mass / volume
Snowpack Density
• Line up sampler perpendicular
face of pit wall
PLAN VIEW
Snowpack Density
• Insert sampler perpendicular
PLAN VIEW
Snowpack Density
• Insert sampler perpendicular
PLAN VIEW
Snowpack Density
• Insert sampler perpendicular
• Do not push into snow wall
PLAN VIEW
Snowpack Density
• Slide lid along open face
PLAN VIEW
Snowpack Density
• Slide lid along open face
PLAN VIEW
Snowpack Density
• Slide lid along open face
PLAN VIEW
Snowpack Density
• Extract sampler perpendicular
PLAN VIEW
Snowpack Density
• Extract sampler perpendicular
PLAN VIEW
Snowpack Density
• Volume of Kelly cutter = 1 L
Mass of sample = density
Shallow Snowpacks
• Less snow, potential for greater relative variation
• Take measurement large cores – eg. MSC sampler with = 7.8 cm
• Smaller stratified samplers – eg. 250 – 500 ml Kelly cutter