Date of Observation: 03/23/2023
Name: Eric Murrow
Zone: Northwest Mountains
Route Description: Washington Gulch TH to Elkton Knob area.
Observed avalanche activity: Yes
Avalanches: I will put most avalanche coding and photos in another ob. No natural avalanche activity near TH. View from the top of Elkton Knob was marginal but buffed debris was visible (few crowns) all over the alpine terrain in the Northwest Mountains and covered many aspects; this drifted over natural activity involved storm snow only. Once on top of Elkton Knob there were a lot of widely-propagating crowns visible in the Upper Slate corridor near Pittsburg and on Purple Ridge below treeline. Easterly aspects seemed to be the bullseye below treeline. HIGH danger occurred at all elevations on Wednesday in the Northwest Mountains.
Weather: Mostly cloudy skies with periodic snow showers; no accumulations. Temperatures were seasonally cool, but solar radiation was enough to moisten snow surfaces on sunny aspects. Winds remained light with some moderate gusting up to 11,200. I saw a few periods of blowing snow across the highest terrain during the day. Settled storm totals up to 32″ at 11,000 feet.
Snowpack: The recent storm snow was thick and supportive to skis on all aspects with ski penetration around 7 to 10 inches. I experienced a few muffled collapses that did not travel far. Periodic sunshine moistened snow surfaces on E-S-W slopes below 11,000 feet but failed to warm enough to make loose avalanches an issue. Snowpack tests on easterly slopes produced moderate propagating results (see image) above the melt/freeze crust at the new/old interface. I traveled near several pieces of avalanche terrain trying to get a remote trigger without result; the storm slab is far too supportive and thick to consider ski cutting anything so I kept a safe distance from steep terrain. A profile on a northerly slope did not produce propagating results on the faceted new/old interface (1-1.5mm facets); I was fairly surprised by this given how weak this interface is.
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- Natural avalanche on westerly terrain of Gothic Mountain. The crown was drifted over so I suspect it ran early on 3/22.
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- Test profile with moderate propagating results on melt/freeze crust at the storm interface.
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- To my surprise, a shaded slope at 11,000 feet did not produce propagating results below the storm snow. The 1.5mm facets at this interface sure seem to be suspect and not trustworthy.
