Ice stalagmite in lava tube

| 7 Comments

Photograph by James Rice.

RiceIceStalagmite_600.jpg

Ice stalagmite in lava tube, Arizona. Mr. Rice evidently sent us this picture in retaliation for our posting last week.

7 Comments

Nice ice!

Ice would be a great mineral to collect, if it wouldn’t end up as a puddle at any comfortable temperature.

Glen Davidson

Ice would be a great mineral to collect, from the Moon. I never understood the apparent lack of interest by NASA and the ESA.

https://me.yahoo.com/a/JxVN0eQFqtmg[…]X_Zhn8#57cad said:

Nice ice!

Ice would be a great mineral to collect, if it wouldn’t end up as a puddle at any comfortable temperature.

Glen Davidson

Even at uncomfortable temperatures, it tends to vaporize over time.

A basic question occurs to me. I had thought that caves tend to have a temperature that is neither freezing in the winter, or hot in the summer. So why is this cave (in Arizona) so cold?

Mark Sturtevant said:

A basic question occurs to me. I had thought that caves tend to have a temperature that is neither freezing in the winter, or hot in the summer. So why is this cave (in Arizona) so cold?

When I toured Mammoth Cave, Kentucky a few years ago, it was said the temperatures deep inside remain in the 50s F all year long (key words, deep inside).

Thus, the photograph may have been taken relatively close to the surface or near an outside entrance. It’s easy to think of Arizona along the likes of lower elevation places like Phoenix and Yuma where overnight winter temperatures are only rarely below freezing for a few overnight hours. In contrast, other parts of Arizona approach 13,000 ft in elevation which of course are colder. http://en.wikipedia.org/wiki/Humphreys_Peak

Some caves have ice in them pretty much all of the time, because they fill up with snow and ice during the winter. Cold air sinks, water sinks, etc., and these caves have openings that go downward a fair way. Then, because warm air doesn’t sink during the summer, little heat enters to warm the frozen stuff, so these caves rarely, if ever, thaw out.

As for this cave, all it would require is a shaft or a higher opening nearby to allow cold to sink in during cold spells for the ice to form and to last for a while.

The ground tends not to warm or cool very quickly. That’s why many caves stay at a fairly steady temperature. But it all depends upon air (and water) flow, so that if cold air enters readily, sinking down, the cave can lose heat a lot faster than surrounding rock/clay, etc. can replenish that heat.

Glen Davidson

James Rice tells us,

Caves tend to take on the average year-round outside temperature, if nothing else acts on them. Caves in high mountain areas will be far cooler than caves in low tropical or desert areas.

As some people speculated, that cave is at a high altitude. It’s right around 7500 feet, near Flagstaff. The area gets several feet of snow in winter, and the snow stays on the ground for several months. Like many caves and almost all lava tubes, that cave’s entrance is a pit, and cold air sinks into it during the winter and has no way out the rest of the year. The soil above is above freezing, but the air inside the cave is well below freezing, at least for many months a year. Within a few miles of this cave, there is a sealed lava tube that must be dug open to get inside. On the same day I visited the cave with the ice stalagmite, I also visited the tube that had to be dug open. That cave had a small lake inside and was much closer to the “ideal” for a cave of being the average of the outside year round temperature (using the term ideal loosely).

Another factor that can change the temperatures in a cave are multiple entrances, especially if the cave also has a significant slope between them, think chimneys. If water is involved, then there will be evaporation, cooling, sinking air, leading to a reverse chimney. This effect can be quite powerful. Bats in large numbers can create local hot spots. Pits, domes, and dead-end passages can cause significant local changes in temperature. Even more importantly when exploring caves, pits and dead-ends can hold dangerous gasses. If a caver notices a sudden temperature change, that’s often a sign of stagnant air and precautions should be taken immediately.

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This page contains a single entry by Matt Young published on December 16, 2013 12:00 PM.

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