Mammoth Basin Snowpack Summary - 2015-04-27 07:53

The backcountry is more accessible than it has been in years. Please help!  ... Click Here to Find Out How

THIS ADVISORY EXPIRED ON April 29, 2015 @ 7:53 am
Avalanche Advisory published on April 27, 2015 @ 7:53 am
Issued by Sue Burak - Inyo National Forest
Avalanche Character 1: Wind Slab
Wind Slab avalanches release naturally during wind events and can be triggered for up to a week after a wind event. They form in lee and cross-loaded terrain features. Avoid them by sticking to wind sheltered or wind scoured areas.

Expect to find areas of wind drifted snow in unusual locations today. Even though many exposed high elevation slopes in the Red Cone and Hammil Lake area have been wind stripped, wind slabs will be found along rocky ribs, mid slope in steep couloirs and even below ridgetops. 
 

Avalanche Character 2: Loose Wet
Loose Wet avalanches occur when water is running through the snowpack, and release at or below the trigger point. Avoid very steep slopes and terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.

Today is the first day of warming for the new snow that fell over the weekend. Pay particular attention to areas around and below rock outcrops where the sun's energy warms the rock and snow immediatel around the rock areas.

Snowpack Discussion

The strong winter storm that dropped over a foot of sweet low density snow blew to the east yesterday. As high pressure built in, hurricane strength north winds blew every snowflake along the crest to Fresno. It’s hard to believe wind slabs formed yesterday but swirling winds below the ridges likely created areas of wind drifted snow.

Over the next week, above freezing temperatures and strong late April sun will quickly spike the avalanche danger as the snow surface gets wet.

The first time new snow gets hit with strong sun and above freezing temperatures, is the most vulnerable time to avalanche. Even though north winds stripped a lot of snow from exposed high elevation slopes, there is new snow in sheltered areas that will get baked over the next few days. This is especially true of east and southeast slopes where the full brunt of the sun’s rays will be felt. Pinwheels of snow and small point releases are a sign the snow is warming up.

recent observations

This morning, winds are blowing 50 to 60 mph from the northeast on the top of Mammoth Mountain. Temperatures are in the mid 20’s at the high elevations with mid elevation locations right around freezing.

High pressure builds today and will push temperatures well above normal through the middle of the week.  

CURRENT CONDITIONS Weather Observations Between June (10,000 ft.) and Mammoth (11,000 ft.)
0600 temperature: 22 deg. F.
Max. temperature in the last 24 hours: 30 deg. F.
Average wind direction during the last 24 hours: N
Average wind speed during the last 24 hours: 60 mph
Maximum wind gust in the last 24 hours: 100 mph
New snowfall in the last 24 hours: T inches
Total snow depth: 12 inches
weather

This morning, winds are blowing 50 to 60 mph from the northeast on the top of Mammoth Mountain. Temperatures are in the mid 20’s at the high elevations with mid elevation locations right around freezing.

High pressure builds today and will push temperatures well above normal through the middle of the week.  

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
  Monday Monday Night Tuesday
Weather: sunny clear sunny
Temperatures: 54-60 deg. F. 34-42 deg. F. 59-67 deg. F.
Wind direction: N N light
Wind speed: 25-30 light light
Expected snowfall: 0 in. 0 in. 0 in.
Over 10,000 ft.
  Monday Monday Night Tuesday
Weather: sunny clear sunny
Temperatures: 45-50 deg. F. 30-36 deg. F. 48-56 deg. F.
Wind direction: N N light
Wind speed: 30-40 light light
Expected snowfall: 0 in. 0 in. 0 in.
Disclaimer

This snowpack summary applies only to backcountry areas outside established ski area boundaries. This snowpack summary only describes general avalanche conditions and local variations always occur. This snowpack summary expires 24 hours after the posted time unless otherwise noted. The information in this snowpack summary is provided by the USDA Forest Service who is solely responsible for its content.

ESAC receives support from ...