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Avalanche Forecast for 2019-04-02 07:00

  • EXPIRED ON April 3, 2019 @ 7:00 am
    Published on April 2, 2019 @ 7:00 am
  • Issued by Aaron Beverly - Mount Shasta Avalanche Center

Conditions will remain wet today, though a few inches of snow is expected near and above treeline. Wind slabs, wet sluffs, and cornice breaks are all problems to be mindful of as you transition from below to above treeline elevations.

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

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

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

Avalanche Problem 1: Wind Slab

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No signs of a wind slab problem were seen yesterday afternoon up to 9,000 feet. Winds have been light and snow moist to wet. If wind slabs exist, expect them high in the alpine regions. As you transition to above treeline elevations where new snow is falling, look for shooting cracks or blocking snow in wind drifted areas of no consequence. This is a sign that wind slabs are forming. Avoid leeward aspects above 35 degrees.

    Avalanche Problem 2: Loose Wet

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    No wet loose avalanches were observed yesterday, though near and below treeline snow was very wet. Continue to be wary of these on steep slopes below treeline. Above freezing temperatures, ankle to knee high boot penetration, very wet snow surfaces, rain-on-snow, and an underlying crust continue to create concern for loose wet avalanches below treeline. Avoid steep slopes where you see roller balls and pinwheels.

    Loose Wet avalanches form in new snow or old surface snow that is warming. Warming temperatures, strong solar radiation, or rain-on-snow make the surface snow damp or wet. As the water content increases, the snow becomes unconsolidated. They start at a point and entrain additional snow as they move down hill, and have a characteristic fan-like shape.

    Avalanche Problem 3: Cornice

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    Dropping temperatures may strengthen cornices today. Nonetheless, many large, overhanging cornices reside at elevations transitioning from rain to snow. Continue to be leary of cornices. Don't be above or below them. A falling cornice could trigger loose wet avalanches.

    Recent Observations

    In the last 24 hours, a little over an inch of rain has fallen near 7,000 ft. Temperatures fell to just below freezing last night. Westerly and southerly winds were light.

    Rain-on-snow and above freezing temperatures turned surface snow near and below treeline very wet. Boot penetration was up to 24 inches. No loose wet avalanches were observed. Rain transitioned to snow above 8,500 feet. About 2.5 inches of new moist snow had accumulated atop a melt-freeze crust by 2 p.m. The snowpack is right side up and no notable column or block tests were observed.

    Weather and Current Conditions

    Weather Summary

    In the next 24 hours, 0.43 inches of precipitable water is expected with most coming before 5 p.m. This will be a mix of rain and snow near and below treeline. Snow levels will be around 6,600 ft. Above treeline snow accumulation could be as much as 5 inches.

    We'll see a lull in precipitation tomorrow, but unsettled weather will kick back in Thursday. Up to 3 inches of water is expected by Sunday.

    24 Hour Weather Station Data @ 5:00 AM

    Weather Station Temp (°F) Wind (mi/hr) Snow (in) Comments
    Cur Min Max Avg Avg Max Gust Dir Depth New Water Equivalent Settlement
    Mt. Shasta City (3540 ft) 41 41 52 44.5 1 N
    Sand Flat (6750 ft) 33 32 38 35 135 0 0 2
    Ski Bowl (7600 ft) 30.5 30.5 38 33.5 179 1.6 1.18 2.8
    Gray Butte (8000 ft) 29 29 36 31.5 10 25 WNW
    Castle Lake (5870 ft) Station not responding
    Mount Eddy (6509 ft) 32.5 32.5 42 36 1 12 S 134.7 0 5
    Ash Creek Bowl (7250 ft)
    Ash Creek Ridge (7895 ft)

    Two Day Mountain Weather Forecast

    Produced in partnership with the Medford NWS

    For 7000 ft to 9000 ft
      Tuesday Tuesday Night Wednesday (5 a.m to 5 p.m.)
    Weather Rain and snow showers. Some thunder is also possible. Chance of precipitation is 90%. Rain and snow showers likely, mainly before 11 p.m. Mostly cloudy. Chance of precipitation is 60%. A 50 percent chance of snow showers. Mostly cloudy.
    Temperature (°F) 37 30 40
    Wind (mi/hr) South 5-10 South 5-10 South 5-10
    Precipitation SWE / Snowfall (in) / 1-3 / <1 / trace
    For 9000 ft to 11000 ft
      Tuesday Tuesday Night Wednesday (5 a.m to 5 p.m.)
    Weather Snow showers. Some thunder is also possible. Chance of precipitation is 100%. Snow showers likely, mainly before 11 p.m. Mostly cloudy. Chance of precipitation is 70%. A 50 percent chance of snow showers. Mostly cloudy.
    Temperature (°F) 24 22 25
    Wind (mi/hr) Southwest 15-20 Southwest 2-4 Southwest 5-10
    Precipitation SWE / Snowfall (in) / 2-4 / <1 / trace

    Season Precipitation for Mount Shasta City

    Period Measured (in) Normal (in) Percent of Normal (%)
    From Oct 1, 2018 (the wet season) 35.34 35.57 99
    Month to Date (since Sep 1, 2019) 0.12 0.11 109
    Year to Date (since Jan 1, 2019) 26.93 20.36 132

    Disclaimer

    This forecast does not apply to Ski Areas or Highways and is for the Mt. Shasta, Castle Lake and Mt. Eddy backcountry. Use this information for guidance only. You may find different conditions in the backcountry and should travel accordingly. This forecast expires on midnight of the date it was posted unless otherwise noted.