Avalanche Advisory: Tuesday - Feb 26, 2019 | Eastern Sierra Avalanche Center

THIS AVALANCHE ADVISORY EXPIRED ON February 27, 2019 @ 6:43 am
Avalanche Advisory published on February 26, 2019 @ 6:43 am

Issued by Steve Mace - ESAC

Bottom Line

How to read the advisory

Moderate Avalanche danger remains today at all elevations. Extreme southwest winds coupled with new snow will lead to increasing avalanche hazard. Evaluate terrain carefully and monitor the weather closely today. Expect avalanche danger to rise quickly as the storm intensifies tonight.

2. Moderate

Above Treeline

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

Near Treeline

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

Below Treeline

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Avalanche Problem 1: Wind Slab

Type ?
Aspect/Elevation ?
Likelihood ?

Certain

Very Likely

Likely

Possible

Unlikely
Size ?

Historic

Very Large

Large

Small

While minimal snow fell overnight very strong sustained winds with gusts over 100 mph were recorded even at lower elevations. As gale force winds continue today, expect to find new slab development on leeward slopes where terrain features encourage drifting. Use surface clues such as blowing snow, recent cornice growth, and uneven snow surface to identify and avoid wind-loaded areas. While northeasterly aspects at upper and mid elevations will be most concerning today, extreme winds can redistribute snow in unpredictable ways. It will be possible to find wind slabs developing on isolated terrain features in more sheltered areas even at lower elevations. Expect the size, sensitivity, and distribution of wind slabs to rise quickly as new snow begins to add up this evening.

advisory discussion

The wind remains the driving force for change throughout the range today. Bannering was noted throughout the range yesterday on ridge tops indicating steady southwest winds however localized winds were much more sporadic. Observations indicated snow was moving around in unpredictable ways leading to more scouring than slab development. If you venture into the backcountry today, don’t be surprised to find many areas striped down to the slick rain crust from Feb. 14/15 and isolated wind slabs developing in unusual places.

With up to a foot of new snow predicted tonight it will be possible to see storm slab development in more sheltered areas by the morning tomorrow. The timing of this storm suggests most accumulation will occur after midnight and snowfall totals will vary significantly across the range with the northern reaches of the forecast zone predicted to receive much more snow than areas further south.

recent observations

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2/25- Mammoth Area, Strong winds in the Sherwins

2/25- Pine Creek, Very windy in Tungstar bowl

2/24- Convict Creek, Snow conditions in Old Mans bowl

2/24- Bishop Area, Basin Mountain Snow Conditions

Weather and CURRENT CONDITIONS

weather summary

Today will be cloudy with 1-3” of new snow possible in the afternoon. Temperatures are expected to be in the high 20’s at upper elevations with strong southwest winds continuing throughout the day. Snowfall is expected to intensify this evening with the bulk of today’s moisture coming after midnight. Up to a foot of new snow is possible at upper elevations. Strong winds will continue out of the southwest tonight as temperatures drop slightly.

Winter weather continues tomorrow with up to 10" of snow likely throughout the day. Temperatures will be in the low 30's and winds are expected to decrease slightly while remaining out of the southwest. Expect a beak in the storm on Thursday and Friday before another system moves into the area this weekend.

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

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

	Tuesday	Tuesday Night	Wednesday
Weather:	Mostly cloudy. Chance of snow. Snow levels below 7000 feet. Chance of precipitation is 50%.	Mostly cloudy. Chance of snow in the evening, then snow after midnight. Snow levels below 7000 feet. Chance of precipitation is 100%.	Mostly cloudy. Snow in the morning, then chance of snow in the afternoon. Snow levels 7000 feet. Chance of precipitation is 100%.
Temperatures:	33 to 41. deg. F.	25 to 31. deg. F.	33 to 41. deg. F.
Mid Slope Winds:	Southwest 30 to 45 mph with gusts to 80 mph.	South 25 to 40 mph with gusts to 85 mph.	Southwest 15 to 30 mph with gusts to 75 mph.
Expected snowfall:	80% probability of 1 to 3 inches. 20% probability of 3 to 6 inches. \| SWE = up to 0.20 inch. in.	80% probability of 6 to 10 inches. 20% probability of 10 to 16 inches. \| SWE = up to 0.70 inch. in.	80% probability of 4 to 8 inches. 20% probability of 8 to 12 inches. \| SWE = 0.30-0.55 inch. in.

Over 10,000 ft.

	Tuesday	Tuesday Night	Wednesday
Weather:	Mostly cloudy. Snow likely, mainly in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 60%.	Cloudy. Chance of snow in the evening, then snow after midnight. Snow levels below 7000 feet. Chance of precipitation is 100%.	Cloudy. Snow in the morning, then snow likely in the afternoon. Snow levels 7000 feet. Chance of precipitation is 100%.
Temperatures:	25 to 31. deg. F.	19 to 24. deg. F.	24 to 30. deg. F.
Ridge Top Winds:	Southwest 50 to 80 mph with gusts to 105 mph.	Southwest 50 to 70 mph with gusts to 105 mph.	Southwest 40 to 60 mph decreasing to 35 to 50 mph in the afternoon. Gusts up to 90 mph.
Expected snowfall:	80% probability of 1 to 3 inches. 20% probability of 3 to 6 inches. \| SWE = up to 0.20 inch. in.	80% probability of 7 to 13 inches. 20% probability of 12 to 18 inches. \| SWE = 0.50-0.75 inch. in.	80% probability of 7 to 10 inches. 20% probability of 10 to 14 inches. \| SWE = 0.50-0.75 inch. 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.