Avalanche Advisory: Tuesday - Apr 16, 2019

THIS AVALANCHE ADVISORY EXPIRED ON April 17, 2019 @ 6:59 am
Avalanche Advisory published on April 16, 2019 @ 6:59 am
Issued by Josh Feinberg - Eastern Sierra Avalanche Center

Tuesday:  1-5” of new snowfall since Monday with strong to moderate SW to W winds continuing today will make wind slab avalanches the primary concern for northern areas of the forecast zone.  Warming temperatures and partly sunny skies will lead to loose wet avalanche concerns as well.  

Wednesday:  Fully sunny skies and much warmer temperatures will make loose wet avalanches the primary concern, with isolated wind slabs developing from northerly breeze a secondary concern.  

Human triggered avalanches will be possible in specific areas at specific times for both Tuesday and Wednesday.  

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Avalanche Problem 1: Wind Slab
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Tuesday:  The northern half of the forecast zone received 3-5” of new snow since Monday, particularly around Mammoth, while southern areas towards Bishop received very little.  Where new wind slabs at upper and mid elevations have formed from strong SW winds human triggering will be possible.  Up to an inch of new snow today with continued moderate W winds will add to this concern.  

Wednesday:  Breezy north winds Tuesday night thru Wednesday will likely redistribute some loose snow into new wind slabs on more southerly facing terrain, particularly at upper elevations. As full sunshine and higher temperatures warm slopes, these new wind deposits on old melt-freeze crusts will likely become more sensitive to a human trigger.  For southern areas of the forecast zone that received little new snow, wind slab concern will be much less.

Avalanche Problem 2: Loose Wet
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Tuesday:  As temperatures warm to above freezing around 10,000’, a greenhouse effect from cloudy skies will likely lead to warming slopes on all aspects especially at mid to low elevations.  Where the sun comes out between the clouds, sunny aspects will warm much more quickly.  As new snow warms for the first time, human triggered and natural point release loose wet avalanches will the possible.  Greater concern will exist for areas such as gullies and couloirs that funnel loose snow into greater concentration resulting in greater consequence. Watch out for what lies above you as rocky slopes warm.  For southern areas of the forecast zone that received very little new snow, loose wet concerns will be much less.     

Wednesday:  Fully sunny skies and above average temperatures reaching the mid 40s at 10,000’ will result in loose wet avalanche concern on sunny aspects as they warm through the day, even at upper elevations.  A good solid overnight re-freeze Tuesday night will delay the start of this concern for the deeper snowpack.  Lower elevation northerly facing slopes could be concerning as well in the afternoon.   

advisory discussion

Timing is everything for springtime skiing and riding, both in terms of avalanche concern and enjoyment of travel.  The early bird often gets the worm.  As slopes warm too much and become wet, punchy and unsupportive, travel becomes no fun and wet slides can become dangerous.  Plan well in regards to your aspects and the time of day, and most importantly be flexible with your goals as you see the conditions around you change.    

Weather and CURRENT CONDITIONS
weather summary

As our latest spring shower that hit the northern half of the forecast zone clears out of the area, lingering flurries on Tuesday could add up to an inch more snow to the 1-5” that fell Monday and Monday night at higher elevations.  Strong SW winds will gradually decrease and shift out of the W Tuesday afternoon, as sun pops out between the clouds and temperatures climb to a bit above freezing around 10,000’.  

Building high pressure will lead to clear skies and cold temperatures Tuesday night with moderate north winds.  Temperatures will climb dramatically on Wednesday well into the mid-40s around 10,000’, with full sunshine and continued breezy north winds.  

Above average warm temperatures, clear skies and sunshine are on tap for the rest of the week before another chance of precipitation returns for the 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: Partly cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 30%. Clear. Sunny.
Temperatures: 35 to 43. deg. F. 21 to 27. deg. F. 46 to 54. deg. F.
Mid Slope Winds: West 15 to 20 mph. Gusts up to 45 mph decreasing to 35 mph in the afternoon. North 15 to 20 mph. Gusts up to 40 mph decreasing to 30 mph after midnight. Light winds.
Expected snowfall: 100% probability up to 1 inch. | SWE = less than 0.10 inch. in. 0 in. 0 in.
Over 10,000 ft.
Tuesday Tuesday Night Wednesday
Weather: Mostly cloudy then becoming partly cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 35%. Clear. Sunny.
Temperatures: 26 to 34. deg. F. 16 to 21. deg. F. 38 to 46. deg. F.
Ridge Top Winds: Southwest 20 to 30 mph with gusts to 50 mph shifting to the west 15 to 20 mph with gusts to 30 mph in the afternoon. North 15 to 25 mph with gusts to 45 mph. North 15 to 25 mph with gusts to 35 mph.
Expected snowfall: 100% probability up to 1 inch. | SWE = less than 0.10 inch. 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.

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