New Snow and Rain on Castle Peak

Location Name: 
Castle Peak
Region: 
Donner Summit Area
Date and time of observation: 
Sat, 02/07/2015 - 12:25
Location Map: 
United States
39° 22' 2.1" N, 120° 21' 13.248" W
See map: Google Maps
US


Red Flags: 
Recent loading by new snow, wind, or rain
Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

6 to 16 inches of wet, dense new snow had fallen since Friday on Castle Peak. This new snow then got rained on up to at least 9000 ft during the end of the storm.

Below 8000 ft, the new snow measured 6-8 inches in depth and remained very wet. Widespread runnels indicated that a significant amount of water had drained through the new snow as rain fell on top of it at the end of the storm last night and this morning. Ski cuts on steep test slopes did not trigger any wet snow instabilities in areas where the snow remained very wet.

Photo 1: Runnels on a NE aspect @ 7600 ft. Photo taken during the morning when skies were partly sunny.

Above 8000 ft. the runnels became less widespread and the new snow depths grew to 14-16 inches. A 1-2 inch thick rain crust existed on or just below the snow surface up to at least 9000 ft. Below the rain crust the new snow remained wet to moist. Snowpit tests did not reveal signs of instability either within the new snow or below the old snow surfaces. Tests indicated that the new snow is consolidating quickly. This new snow was supportable and a skier would only sink .5 to 2 inches into the new snow. In many areas the newly formed rain crust masqueraded as the old crusts at the base of the new snow since the strong winds had already deposited some dirt, twigs, and other small debris on top of it.

Snowpit is from a W aspect on the NW side of Castle @ 8800 ft.

 

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
75% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Moderate
Precipitation: 
Snow
Air temperature trend: 
Cooling
Wind Direction: 
Southwest
Accumulation rate: 
Greater than 1 in. per hour
More detailed information about the weather: 

The morning started out partly sunny and warm. By noon a thick layer of clouds had moved in and temperatures fell. Light snowfall started around noon and by 12:30 snow was falling at about 1 in/hr above 7500 ft.