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

cutter/teeth scale snow tube

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 tube 3. Insert tube vertically

SWE measurement 1. Clean the snow tube 2. Tare the snow tube 3. Insert tube vertically 4. Rotate tube into snowpack

SWE measurement 1. Clean the snow tube 2. Tare the snow tube 3. Insert tube vertically 4. Rotate tube into snowpack 5. Twist sharply at bottom

1. Clean the snow tube 3. Insert tube perpendicular 4. Rotate tube into snowpack 5. Twist sharply at bottom 6. Pull out vertically

1. Clean the snow tube 3. Insert tube perpendicular 4. Rotate tube into snowpack 5. Twist sharply at bottom 6. Pull out vertically 7. If an entire column has been removed, weigh tube with core

1. Clean the snow tube 3. Insert tube perpendicular 4. Rotate tube into snowpack 5. Twist sharply at bottom 6. Pull out vertically 7. If an entire column has been removed, weigh tube with core

Snowpack Density • Average density = SWE / depth

Snowpack Density Stratified densities from snow pits 1. 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 F = 7.8 cm • Smaller stratified samplers – eg. 250 – 500 ml Kelly cutter