Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 2–3
A layer of surface hoar buried at the end of January has been the most reactive where the overlying slab approaches two feet deep. In some places, these grains continue to fail in snowpack tests below slabs closer to three feet deep. Recent field observations suggest these grains are more widely preserved near the treeline and down to about 5,000 feet. In addition to buried surface hoar, a pile of weak (F to 4F) facets sits below across most northerly and easterly aspects, while a faceted crust looms below on more sunny and westerly aspects. Lesser snowpack settlement as a function of very cold temperatures over the next few days will prevent weak grains from breaking down and bonding anytime soon.
(2/6/2025)
One of the culprit persistent weak grains underneath the storm slab - surface hoar. Before burial, these grains were almost 20 mm in size, they have been reduced to 10 to 15 mm and well-preserved in spots. West Cabinet Mountains. February 6, 2025.
Photo: Chris Bilbrey