Book 12, Question 94
Why Does Steam From Hot Springs Look Bigger on Cold or Damp Days?
The white cloud above a hot spring is not really steam, because real steam is invisible! It is made of tiny droplets of liquid water floating in the air. It looks biggest on cold or damp days.
More fun facts
- Geologists say the plumes rising from thermal areas are condensed fog, so how steamy a geyser basin looks depends on the air's temperature and humidity.
- On a warm, dry summer day, even Norris Geyser Basin, one of Yellowstone's most active areas, can look quiet except where a geyser is erupting.
- On cold or very humid days, steam plumes seem to rise from every corner of a geyser basin.
- Roaring Mountain in Yellowstone is dotted with steam vents and looks especially dramatic on cool days, when the steam is easier to see.
- In winter, warm ground melts bare patches in the snow, so satellites can spot hot areas that are hard to visit in person.
- Scientists find the hottest zones most easily when snow is over 1 meter deep and the air has stayed below about minus 7 degrees Celsius for several days.
- Studying winter satellite pictures going back to 2002 revealed several Yellowstone hot areas that had never been mapped.
Sources: npshistory.com, National Park Service, U.S. Geological Survey
Questions kids ask
Is the hot spring hotter on a cold day?
Not necessarily. The cold air just makes more of the invisible steam turn into visible fog.
Can snow help scientists find hot ground?
Yes. Warm ground melts the snow above it, so bare patches in winter satellite pictures point to hidden thermal areas.