April 11, 2017


Front Range:


Glen Alps, South Fork Campbell Creek, Ramp, Williwaw Lakes, Ballpark, False Peak, Glen Alps

Obvious signs of instability (red flags):

  • Recent natural wet loose avalanches up to D1.5 on solar aspects (typically starting as point releases from steep, rocky terrain)
  • Evidence of natural persistent slab avalanches up to D2.5 on upper elevation leeward terrain from last storm cycle


  • Sunny with calm wind and alpine temps from the upper 30s to lower 20s

Surface conditions:

  • Supportable melt-freeze in the valleys and on solar aspects softening to ripe corn by afternoon (staying supportable throughout the day expect in thin areas)
  • Ankle to knee deep spring powder on northerly aspects


Having now been subjected to days of melt-freeze cycle, the snowpack on solar aspects and at the mid elevations is generally stable after sunset and in the morning with diurnal warming and solar radiation decreasing stability through the day.  It will be important to watch temperature fluctuations, paying close attention to when temperatures do not drop below freezing overnight.  A temperature inversion could create such a scenario at the upper elevations.  An interruption in the melt-freeze cycle could significantly increase avalanche danger, as stability is dependent on the nightly re-freeze.

Complex terrain on northerly aspects (that cannot be effectively managed) are likely harboring dangerous persistent slabs due to the faceted layer, from the month long dry spell, that is sandwiched between two hard slabs.  This setup was easily identified with pole probing and handpits on northerly terrain that had not previously sluffed or avalanched during the last storm cycle.  This setup was still collapsing (whumphing) on multiple aspects last weekend in both the South and North Fork Eagle River areas.  While no collapsing has been reported in the Front Range this week, this setup is still suspect where it exists; it could produce large, unpredictable, and dangerous avalanches.