Avalanche Advisory: Tuesday - Jan 5, 2021 | Eastern Sierra Avalanche Center

THIS AVALANCHE ADVISORY EXPIRED ON January 6, 2021 @ 6:40 am
Avalanche Advisory published on January 5, 2021 @ 6:40 am

Issued by Josh Feinberg - Eastern Sierra Avalanche Center

Bottom Line

MODERATE WIND-SLAB avalanche danger exists at all elevations this morning due to yesterday and last night’s extreme SW winds and 1-3” of new snow. Watch for pockets of dense new snow on the leeward side of terrain features, even in lower elevation areas typically thought of as sheltered. Slopes facing NW-NE-SE are of greatest concern.

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

1-3” of new dense snow fell yesterday afternoon thru last night with extreme SW winds at all elevations with gusts up to 120mph over ridges. Although this is far less snowfall than we hoped for, it is still enough to create some dangerous wind slabs. With such strong winds, these slabs could be found in erratic unexpected places. Pay attention to snow surfaces as you travel, and be weary of dense hollow-sounding snow. Winds have died down considerably, so signs of blowing snow won’t help you identify where these may lie, but fresh cornice formation could. Remember with our shallow obstacle-ridden snowpack, even a small slide could end in injury or worse, especially if it ends in a gully or occurs above a cliff. A slight possibility exists that a windslab avalanche could be enough force to trigger a buried weak layer and result in a larger than expected avalanche.

advisory discussion

Before yesterday we believed we had beaten the dead horse named “persistent weak layer” enough. But with yesterday’s snow forecast suggesting that a foot of snow could be possible, we thought we might be hearing it’s faint whinnying again from down-under. Alas, the storm stayed mostly north, and the minimal new snow load that we got was barely enough to awaken a mouse, let alone some buried facets.

There is still weak snow buried in many places. While pit-tests will likely continue to show that it has potential to fail, an actual persistent slab avalanche is very unlikely without a significant new load of snow to offset the snowpack’s balance. That being said, it is not impossible that an isolated wind-loaded area exists where a buried weak layer could be triggered. It's always important to practice safe travel protocols just in case. We will keep monitoring it, with hopes that a new heavy load will come before too long!

recent observations

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-1/4 – VA Lakes - Red Lake Bowl: light snowfall, strong winds, dense snow deposits

-1/4 – VA Lakes – Red Lake Bowl: Small dense windslabs 2-6” thick

-1/4 – Mammoth – Sherwins: light snowfall, strong winds, thin dense snow deposits

1/03 – June Lake area –Hemlock Ridge: Snow Conditions

1/03 –Mammoth Area – Lakes Basin: Warm temps

1/03 –Bishop Area –NF Bishop Creek: Minimal to Nonexistent snow

Weather and CURRENT CONDITIONS

weather summary

Dry conditions will prevail until a chance of light snow returns for Friday. Extreme SW winds yesterday and overnight have died down, with gusts expected this morning to reach up to 40mph before becoming light out of the W this afternoon. Expect mostly sunny skies today with temperatures reaching the mid-30s around 10,000’.

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 sunny. Snow levels below 7000 feet. Chance of precipitation is 0%.	Clear then becoming partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%.	Mostly cloudy. Snow levels below 7000 feet increasing to 7000 feet in the afternoon. Chance of precipitation is 5%.
Temperatures:	35 to 41. deg. F.	21 to 26. deg. F.	35 to 43. deg. F.
Mid Slope Winds:	Light winds. Gusts up to 30 mph in the morning.	Light winds.	Light winds.
Expected snowfall:	0 in.	0 in.	0 in.

Over 10,000 ft.

	Tuesday	Tuesday Night	Wednesday
Weather:	Mostly sunny. Snow levels below 7000 feet. Chance of precipitation is 0%.	Partly cloudy then becoming mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%.	Mostly cloudy. Snow levels below 7000 feet increasing to 7000 feet in the afternoon. Chance of precipitation is 10%.
Temperatures:	29 to 35. deg. F.	17 to 22. deg. F.	28 to 34. deg. F.
Ridge Top Winds:	West 15 to 25 mph with gusts to 40 mph in the morning becoming light.	Light winds becoming southwest around 15 mph with gusts to 25 mph after midnight.	Southwest around 15 mph with gusts to 25 mph.
Expected snowfall:	0 in.	0 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.