The natural environment and history of Kalispell’s West Valley area
by Skip Via
skip@westvalleynaturalists.org
Editor’s note: More details on what constitutes hoar frost, rime frost, and rime ice may be found in this article on our web site: Hoar Frost or Rime Ice, or Something else?
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On December 30 and 31, 2025, the conditions in the West Valley were perfect for creating rime frost: low, dense fog, cold temperatures, and steady winds.
by Skip Via
skip@westvalleynaturalists.org
A brief photoessay of some beautifully varied ice, snow and frost manifestations from the north shore of Flathead Lake. As you approach the edge of the open water, marvel at the effects of wave action, multiple thawing and refreezing, snow, wind, and temperature changes on the ice. Also look carefully to find some stunning examples of tiny air bubbles trapped in clear ice as they try to make their way to the surface. Something new in every step.
If you go, wear spikes and bring poles. Also, remember that this area is closed on March 1 to protect critical breeding habitat for a wide variety of birds.
by Skip Via
skip@westvalleynaturalists.org
I woke up on December 29, after two days of dense fog, to see everything–leaves, grasses, fencing wire, pine needles–coated in a beautiful layer of hoar frost.
But wait…hoar frost occurs only in very specific conditions: namely cold, clear, and windless nights with low humidity, when the rapid radiant heat loss from surfaces causes water vapor–not liquid water droplets, as in fog–to form delicate, needle-like crystals on those surfaces. The previous two nights had been anything but cloudless with low humidity. You could feel the cold fog droplets on your face when you walked.
But it sure LOOKS like hoar frost. What’s going on here?
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