Avalanche Advisory: Sunday - Feb 2, 2020 | Eastern Sierra Avalanche Center

THIS AVALANCHE ADVISORY EXPIRED ON February 3, 2020 @ 6:24 am
Avalanche Advisory published on February 2, 2020 @ 6:24 am

Issued by Steve Mace - ESAC

Bottom Line

How to read the advisory

Low avalanche danger persists at all elevations today. Fresh sensitive wind slabs may develop late this afternoon as a brief winter storm brings light snow showers and very strong SW winds. Be prepared for avalanche danger to rise this evening if we see higher snow totals than expected.

1. Low

Above Treeline

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

Near Treeline

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

Below Treeline

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Avalanche Problem 1: Wind Slab

Type ?
Aspect/Elevation ?
Likelihood ?

Certain

Very Likely

Likely

Possible

Unlikely
Size ?

Historic

Very Large

Large

Small

Strong to gale force southwesterly winds will impact our area accompanied by 1-4” of snow. It is likely that we will not see any snowfall until late this afternoon or during the evening hours. Timing will be everything today. If and when we start to see fresh snow accumulate, we can also expect to see fresh sensitive wind slabs begin to form on northerly and easterly aspects at mid and upper elevations. It will be important to remember that strong winds can distribute snow in unexpected ways. Don’t be surprised to find wind deposits in more sheltered areas, at lower elevations, and further down slopes than you may typically expect to find them. Do your own localized assessments and be suspect of terrain features that encourage drifting such as the leeward sides of ridgelines, gully features, and cross-loaded depressions.

advisory discussion

Today promises a big change both in terms of the weather as well as the surface conditions. The last couple of days have been unseasonably warm which resulted in substantial surface warming throughout the range on all aspects and even at upper elevations. A significant cold front is expected to impact the area today and we can expect the snow surface to harden into a variety of hard slick surfaces. With only limited amounts of new snow on tap for this evening, it is not likely that we will see a significant increase in avalanche activity. However, this new hard and variable surface will pose its own hazards. Travel may be difficult and unpleasant in areas where the crust is breakable or where recent tracks have refrozen. Be wary of areas with hard slick and supportable crusts where a fall may result in a slide for life situation. An ice ax, and boot or ski crampons may be necessary tools today for some objectives. In addition, our snowpack remains highly variable in terms of depth and distribution. Be on the lookout for shallowly buried obstacles and realize that coverage can change drastically over a very short distance

recent observations

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02/01- Buttermilk Country - Snow conditions on the SE shoulder of Basin

02/01- Virginia Lakes - variable surface conditions

02/01- McGee Creek - Significant surface warming, Sizable Loose wet activity

01/31- Mammoth Area- Snow conditions, signs of warming

01/31- June Lake - Solar warming, variable surface textures

Weather and CURRENT CONDITIONS

weather summary

After two spring-like days with near record-setting warm temperatures, we will be returning to more seasonally appropriate conditions today. Temperatures will drop throughout the day as a significant cold front impacts the area. Highs in the mid 30°s below 10,000’ this morning will drop into the low teens or even the single digits by this evening. Increasing southwesterly winds today will impact the area bringing mid-slope gusts up to 80 mph and ridgetop gusts as high 100 mph. This cold front will bring with it a brief winter storm that may result in 1-4” of new snow.

Tomorrow promises to remain cold with daytime highs of 13°-20° F at lower elevations. Winds will remain strong as they shift to a more northerly direction.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS

For 8,000 ft. to 10,000 ft.

	Sunday	Sunday Night	Monday
Weather:	Sunny. Chance of snow in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 35%.	Partly cloudy then becoming mostly cloudy. Snow likely. Snow levels below 7000 feet. Chance of precipitation is 60%.	Partly cloudy.
Temperatures:	35 to 45 in the morning, dropping through the day. deg. F.	5 to 13. deg. F.	13 to 21. deg. F.
Mid Slope Winds:	Southwest 20 to 30 mph increasing to 30 to 50 mph in the afternoon. Gusts up to 80 mph.	West 25 to 35 mph shifting to the northwest 15 to 30 mph after midnight. Gusts up to 60 mph.	North 15 to 25 mph with gusts to 40 mph.
Expected snowfall:	70% probability up to 2 inches. 30% probability of 2 to 3 inches. \| SWE = less than 0.10 inch. in.	Up to 2 inches. \| SWE = less than 0.10 inch. in.	0 in.

Over 10,000 ft.

	Sunday	Sunday Night	Monday
Weather:	Sunny then becoming partly cloudy. Chance of snow in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 40%.	Mostly cloudy. Snow likely. Snow levels below 7000 feet. Chance of precipitation is 55%.	Partly cloudy.
Temperatures:	27 to 35 in the morning, dropping through the day. deg. F.	1 below to 5 above zero. deg. F.	6 to 14. deg. F.
Ridge Top Winds:	Southwest 55 to 75 mph with gusts to 95 mph.	West 30 to 40 mph with gusts to 75 mph shifting to the north 20 to 35 mph with gusts to 50 mph after midnight.	North 20 to 35 mph with gusts to 50 mph.
Expected snowfall:	70% probability up to 1 inch. 30% probability of 2 to 3 inches. \| SWE = less than 0.10 inch. in.	Up to 2 inches. \| SWE = less than 0.10 inch. in.	0 in.

Disclaimer

This Avalanche Advisory is designed to generally describe avalanche conditions where local variations always occur. This product only applies to backcountry areas located outside established ski area boundaries. The information in this Avalanche Advisory is provided by the Eastern Sierra Avalanche Center, who is solely responsible for its content.