Avalanche Advisory: Friday - Mar 30, 2018

 
 
 
 
 
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THIS AVALANCHE ADVISORY EXPIRED ON March 31, 2018 @ 6:33 am
Avalanche Advisory published on March 30, 2018 @ 6:33 am
Issued by Clancy Nelson - Eastern Sierra Avalanche Center

The avalanche danger will again rise to MODERATE today as slopes warm and thaw. Watch for rollerballs coming down the slope around you and boot-top penetration into wet snow as indicators that stability is deteriorating. Loose wet avalanches may originate from rocky outcrops and vegetation. Cirques and gullies will warm faster than open slopes. Timing is critical to avoid the problem. Plan to be off of steep terrain before the surface snow becomes too wet.

Prior to thawing, hard snow surfaces will create slide-for-life conditions where a simple fall on steep slopes could result in higher consequences. Crampons and an ice ax may reduce your vulnerability.

2. Moderate

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

2. Moderate

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

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Loose Wet
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    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Loose wet avalanches will again be a problem, especially near terrain that will receive and retain the most solar heating, by mid-day. The snow will thaw first in rocky cirques and gullies, and on tree-covered slopes. Snow pinwheels and boot-top-deep penetration into wet snow are telltale signs of increasing instability. Small point releases indicate that larger wet avalanches are becoming possible. Time your day to be off of slopes before the surface snow loses cohesion.

advisory discussion

A temperature inversion last night, and mostly clear skies, helped middle and lower elevation slopes re-freeze. However, some upper elevation weather sensors are reporting night time lows near or above freezing. Above average temperatures again today may thaw the snowpack quickly. Sunny skies and light winds can increase initial warming. Thin and hazy clouds that are forecasted for this afternoon may hold in solar radiation which could worsen surface snow melting on all aspects. As surface snow melts it loses cohesion and becomes increasingly unstable. Loose wet avalanches become possible, especially where the thawing is fastest and penetrates the snowpack deepest. Rollerballs or pinwheels and small sluffing can indicate that conditions are deteriorating. One way you can track the warming yourself is by noting how deeply your feet sink into the snow. Boot-top penetration means that the snow may be wet enough to slide. Plan to be off of warming slopes before that happens. Some loose wet avalanches big enough to injure or bury a person could be possible today. But even smaller wet sluffs can be dangerous. Several recent avalanches were observed yesterday that were relatively small but would have slammed a trapped rider into trees. Be aware of terrain traps around you.

As the snow melts at upper elevations rockfall and cornice failure can become problems as well. Early in the day, before thawing, hard frozen surfaces may cause slide-for-life conditions. A simple fall in steep terrain may have increased consequences. In many instances this can be a greater danger than small loose wet sluffs. Crampons, ice axes, and a helmet will help reduce your vulnerability if you are exposed to the risk of a slip and fall.

Weather and CURRENT CONDITIONS
weather summary

Above average temperatures will continue into the weekend with daytime highs running around 10 degrees or so above average. Saturday looks like the cloudiest day with clearing possible by Sunday.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Friday Friday Night Saturday
Weather: Sunny then becoming partly cloudy. Partly cloudy. Partly cloudy then becoming mostly cloudy.
Temperatures: 52 to 60 deg. F. 28 to 33 deg. F. 50 to 58 deg. F.
Wind Direction: Light wings. W Light winds.
Wind Speed: Light winds. 10 to 15 mph in the evening becoming light. Light winds.
Expected snowfall: 0 in. 0 in. 0 in.
Over 10,000 ft.
Friday Friday Night Saturday
Weather: Partly cloudy. Partly cloudy. Partly cloudy then becoming mostly cloudy.
Temperatures: 44 to 49 deg. F. 26 to 31 deg. F. 43 to 48 deg. F.
Wind Direction: W W W
Wind Speed: 10 to 15 mph. 10 to 15 mph in the evening becoming light. 10 to 15 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 Snowpack Summary is provided by the Eastern Sierra Avalanche Center, who is solely responsible for its content.

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