For hikers in mountainous and / or northern areas, and especially for hikers that also bring along a fishing rod on their trips, there are two milestones that fairly reliably mark the start and end of the summer and fall seasons. Ice out is when lakes are free of winter ice and ice in is when they freeze over again. Ice in and ice out dates vary regionally, and in mountainous areas there are also significant variations even within the same range.

Elevation and aspect are the biggest contributors. Put simply, high lakes that are tucked up closely on the north side of slopes (therefore getting lots of shade) will typically freeze earlier and thaw later than lower elevation lakes that are in more open areas or are south facing. It’s extremely time and weather dependent, but legendary fishing conditions can occur before ice in and right after ice out.

Ice Out and Ice In Hiking

I’ve found that backpacking at ice out is a really rewarding time of year, although it does have a few challenges. There are often still snow drifts to contend with around the lake and trail conditions can be snowy, muddy, or in great shape – and often a mix of all three within the same mile, and using a pair of backcountry snowshoes may even be the best form of travel. Creeks are typically not at peak run off levels, so I've found crossing them is usually possible. I often find myself eagerly hiking up to subalpine lakes in mid-June (usually just beginning to thaw in most areas of the Northern Rockies, with most ice-free by July) to enjoy seeing the small-scale freeze/thaw cycle play out and imagining it on the grand scale of huge glaciers that shaped the mountains.

Resting on top of snow on a sunny June day, with the snow radiating the sun back out to make it feel even warmer, and looking at a frozen lake is a sublime experience that is always worth the postholing and sloppy conditions to get there.

Editor's Note: This Jargon installment originally appeared in Issue 49 of TrailGroove Magazine. You can read the original article here.