Steamboat & Flat Tops

Avalanche

Dylan Craaybeek, Austin DiVesta · Feb 13, 2023 · Steamboat & Flat Tops

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Weather

Cold morning (3F) in Craig warming up to 24F at the trailhead by 8:45. Cloud coverage remained between Few and Scattered throughout the day with winds picking up to Light with Moderate gusts around noon.

Snowpack

The average height of snow (HS) around Ripple Creek Pass is consistently over two meters deep. There is surface hoar developing on the snow surface fairly widespread around Vaughan Lake on all slopes except for southerly slopes steeper than around 20 degrees where the incoming shortwave radiation melted the snow surface and is developing melt-freeze crusts (MFcr). A buried layer of surface hoar was identified after extended column tests (ECT) showed propagating results on it about 60cm down on northerly aspects and about 30cm down on southerly aspects. The buried surface hoar layer was identified on north through southeast-facing slopes with ECTP results after 20-30 taps on north through east-facing slopes and propagating results after 5-15 taps on southeast and some south-facing slopes where the buried surface hoar was shallower and resting on top of a MFcr. This buried surface hoar layer was found lower down in Poose Creek but was much smaller and only got non-propagating results in ECTs after 25+ taps. This layer is likely isolated to the Vaughan Lake area and adjacent meadows.

Avalanche

A very interesting natural avalanche cycle occurred within the past couple of weeks in this area of all Glide avalanches on numerous different substrates but all smooth, planar slopes. Best guess is this avalanche cycle occurred around January 22-26 during the first period of more than 2 days of no snowfall and warm (near freezing) temperatures right before the next stormy period that lasted until our trip. There was roughly 60cm of snow resting on the ground inside of the glide cracks which corresponds to the accumulated precipitation at the Ripple Creek SNOTEL. Best guess is the cycle occurred on January 24, 2023.