The last avalanche forecast for the 2023-2024 season will post on April 21st. Thank you to all who contributed to the avalanche center this season through observations, volunteer time, and/or financial contributions.

avalanche castle apron

Location Name: apron backside castle peak Region: Donner Summit Area Observation Date & Time: Friday, December 2, 2022 - 09:22
Location: 39.371684, -120.339953 See map: CalTopo	Is this an Avalanche Observation?: Yes Conditions Alerts: Avalanche Activity Other Signs of Instability (cracking, whumpfing, collapsing) Other Signs of Instability (cracking, whumpfing, collapsing)›Collapsing / whumpfing noises Other Signs of Instability (cracking, whumpfing, collapsing)›Shooting Cracks Persistent Problem Recent Loading Recent Loading›Blowing Snow Recent Loading›More Than a Foot of New Snow Recent Loading›Snowfall Rates of More Than 1 in/hr Terrain Alerts: Slopes Steeper than 30 degrees Obvious Slide Path Trigger Points Terrain Matches the Advisory

Location Name:

apron backside castle peak

Region:

Donner Summit Area

Observation Date & Time:

Friday, December 2, 2022 - 09:22

Location:

39.371684, -120.339953

See map: CalTopo

Is this an Avalanche Observation?:

Yes

Conditions Alerts:

Avalanche Activity
Other Signs of Instability (cracking, whumpfing, collapsing)
Other Signs of Instability (cracking, whumpfing, collapsing)›Collapsing / whumpfing noises
Other Signs of Instability (cracking, whumpfing, collapsing)›Shooting Cracks
Persistent Problem
Recent Loading
Recent Loading›Blowing Snow
Recent Loading›More Than a Foot of New Snow
Recent Loading›Snowfall Rates of More Than 1 in/hr

Terrain Alerts:

Slopes Steeper than 30 degrees

Obvious Slide Path

Trigger Points

Terrain Matches the Advisory

Observation made by: Public

Tabs

Observation

Description of Snow, Weather, and Avalanche Conditions:

I was climbing high up on the apron west to east and got some good settling just west of those big old-growth fur trees in pic. 5 steps east of trees got more settling and a crack that ran east and uphill about 20yds and then it ripped out big time. 2-3ft crown 50 yds wide. Ran top to bottom. Couldn’t tell if it got into old snow or just lots of wind loading. Another 2ft on top of this instability, and things could get sketchy out there. Proceed with caution.

Avalanche Details

Avalanche Type:

Storm Slab

Failure Plane/Weak Layer:

Storm Snow

Trigger

Trigger:

Skier

Trigger Modifier:

Remotely Triggered

Terrain

Start Zone Slope Angle:

45degrees

Aspect:

Northeast

Starting Elevation:

above-treeline

Size

Destructive Size:

D3 Could bury and destroy a car, damage a truck, destroy a wood frame house, or break a few trees.

Relative Size:

R5 Very Large

Crown Height:

3 ft

Avalanche Width (Average width):

150ft.

Avalanche Length (Vertical Run):

900ft.

Sponsors:

This website is owned and maintained by the non-profit arm of the Sierra Avalanche Center. Some of the content is updated by the USDA avalanche forecasters including the forecasts and some observational data. The USDA is not responsible for any advertising, fund-raising events/information, or sponsorship information, or other content not related to the forecasts and the data pertaining to the forecasts.

Forecast Links

Subscriptions

Forecast Tutorials

Observations

Incidents

Submit Observations

Subscriptions

Remote Weather Stations

National Weather Service

Model Forecasts

Local Resources

The SAC Daily Flow

Forecast Tutorials

Other Resources

avalanche castle apron

Conditions Alerts:

Tabs

Sponsors:

Forecast Links

Subscriptions

Forecast Tutorials

Observations

Incidents

Submit Observations

Subscriptions

Remote Weather Stations

National Weather Service

Model Forecasts

Local Resources

The SAC Daily Flow

Forecast Tutorials

Other Resources

avalanche castle apron

Conditions Alerts:

Tabs

Search form

Follow Us

Sponsors: