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Avalanche Advisory for 2018-04-07 06:50

  • EXPIRED ON April 8, 2018 @ 6:50 am
    Published on April 7, 2018 @ 6:50 am
  • Issued by Nick Meyers - Shasta-Trinity National Forest
  • April 7, 2018 @ 6:50 am

    Advisory Hotline: (530) 926-9613

  • Despite several inches of water over the past 48 hours, the avalanche danger remains LOW for all aspects and elevations. Normal caution is advised but continue to watch out for isolated wind slabs well above treeline, in alpine areas above 10,000 feet. Overall, the wet and warm nature of this storm followed by cooling temperatures today will keep natural and human triggered avalanches unlikely.

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

Avalanche Problem 1: Normal Caution

  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Generally safe avalanche conditions exist in the backcountry. Both natural and human triggered avalanches are unlikely. Remember, LOW avalanche danger does not mean NO avalanche danger. In alpine areas above 10,000 feet, watch for small isolated wind slabs where areas of drifting have occurred.

Advisory Discussion

Periods of rain and snow over the past 48 hours has provided 5-8 inches of grade-A Shasta plaster to elevations above 6,800 feet. A cold front descends upon the mountain today and should keep snow instabilities at harbor. The warm and wet nature of this storm has arguably done more harm than good for our snowpack. Regardless, the handful of inches of new snow has helped smooth things out and hopefully will contribute to a short lived,  but fun spring ski season.

Recent Observations

Yesterday, mixed rain and snow fell on the mountain. Snow levels dropped as low as 6,500 feet during the storm, however warming temperatures drove snow levels to upwards of 9 to 10,000 feet by the evening. At 1300 hours, 5 inches of heavy, very wet snow was observed at Bunny Flat. Near treeline, snow accumulation was a tad more. Visibility was poor above treeline. Overnight, 3 inches of wet snow fell. In the past 24 hours, 2.39 inches of water was recorded at the Old Ski Bowl weather station tipping bucket. Only .78 inches water was observed in Mount Shasta City. Winds have been remarkably light on Gray Butte, averaging 10 mi/hr with gusts into the 20-30 mi/hr range. No recent avalanches or signs of instability have been observed. No blowing snow or wind loading was observed due to the heavy, wet nature of the storm.

Weather and Current Conditions

Weather Summary

A Winter Weather Advisory has been issued for areas above 4,500 feet in the southern Oregon Cascades and Siskiyou Mountains this morning into Sunday. It will be wet and windy again, however a cold front will move quickly into the area today. This will bring periods of fading rain and snow. Precipitation amounts are not impressive for Mount Shasta (.32" today). Snow levels should bottom out at about 6,500 feet and new snow accumulation will not be spectacular. Winds will continue to blow in exposed areas above treeline on the mountain, 30-40 mi/hr with gusts higher. Areas to the north like Crater Lake and Diamond Lake look to get hit the hardest with this storm. An active weather pattern will continue through next week. A short-lived but strong warming trend will begin on Sunday with highs near normal and decreasing clouds. High temps on Monday will be well above normal. Light to moderate rain is expected Tuesday through Friday.

24 Hour Weather Station Data @ 4:00 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) 49 42 50 47.5 3 N
Sand Flat (6750 ft) station down
Ski Bowl (7600 ft) 36.5 30 37 34.5 77.3 3 2.39 3.2
Gray Butte (8000 ft) 36 28 36.5 33 10 25 WSW
Castle Lake (5870 ft) 40 32.5 40 35.5 18.6 0.1 0.2
Mount Eddy (6509 ft) 38.5 33 39 37 2 11 S 39.9 1.4 1
Ash Creek Bowl (7250 ft) station down
Ash Creek Ridge (7895 ft) station down

Two Day Mountain Weather Forecast

Produced in partnership with the Medford NWS

For 7000 ft to 9000 ft
  Saturday Saturday Night Sunday
Weather Breezy, rain this morning and showery this afternoon. Breezy, rain and snow showers. Not as cool, mostly cloudy, slight chance of snow showers in the morning, then partly cloudy.
Temperature (°F) 39 29 45
Wind Direction SW SW SW
Wind Speed (mi/hr) 10-20 10-15 10-15
Expected Snowfall (in) 2-4 1-2 0-.5
For 9000 ft to 11000 ft
  Saturday Saturday Night Sunday
Weather Snow before 11am, then showery after. Temperatures falling. Windy. Snow showers, windy. Slight chance of snow showers in the morning, trending toward partly cloudy. Windy.
Temperature (°F) 21 17 26
Wind Direction SW SW W
Wind Speed (mi/hr) 40-50 40-50 40-50
Expected Snowfall (in) 3-6 1-3 0-.5

Season Precipitation for Mount Shasta City

Period Measured (in) Normal (in) Percent of Normal (%)
From Oct 1, 2017 (the wet season) 16.84 36.16 47
Month to Date (since Jun 1, 2018) 0.89 0.70 127
Year to Date (since Jan 1, 2018) 11.01 20.95 53

Disclaimer

This advisory does not apply to Ski Areas or Highways and is for the Mount Shasta, Castle Lake and Mount Eddy backcountry. Use this information for guidance only. You may find different conditions in the backcountry and should travel accordingly.