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DOES CRATER LAKE EVER FREEZE?
by Steve Mark, Park Historian
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Crater Lake in 1949
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Countless numbers of visitors ask this question every year. Such an
event is a very rare occurrence which may happen only once in a
lifetime. The last winter Crater Lake "froze over" was in 1949, when an
icy layer completely covered it for over two months. Prior to 1949, the
only other time this was reported to have happened was for four days
during February, 1924.
Like most large bodies of water, Crater Lake is a heat reservoir
where temperatures do not fluctuate greatly except near the surface.
Below about 200 feet, water temperature remains at a perpetual 38
degrees Fahrenheit. When surface water is cooled by frigid air, it
becomes denser and sinks, forcing up less dense warmer water. This
usually prevents ice formation, but in 1949 the upper 200 feet of water
cooled down to 32 degrees and the surface water even lower.
On March 14, 1949, two park rangers set out to investigate this
unusual event. Using a predetermined route, they walked to Wizard
Island. They descended into the caldera from Rim Village and found the
ice thickness to be about 12 inches when they reached the shoreline. The
ice layer was reduced to two inches at a spot where the lake is 1000
feet deep. At this point, the pair discovered watery slush filling their
tracks, so they made a hasty advance to the island.
Since retracing their steps was out of the question, the two rangers
decided to take the shortest route across the lake and go back along the
shore. They crossed Skell Channel, where the ice had formed up to four
feet thick, with no difficulties; but their most difficult hurdle still
lay ahead. That was the 900 foot ascent back to Rim Village. This was
made in snow averaging 150 inches deep at an angle of approximately 45
degrees. With perseverance and little more than luck, both of them
returned that afternoon with their observations.
Crater Lake remained a giant expanse of white until almost mid May
of 1949. Since then, the closest it has come to a repeat performance was
during April 1983 when ice covered approximately 95 percent of the lake.
We have not had such a "hard" winter since, but this could be one of
those years....
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