By State › Wyoming

Wyoming: Overview

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Everything in the main manual and the skill guides applies in Wyoming exactly as written. What’s different here is the specific hazard profile and the state, local, and legal context around it. This page is the starting point; the other three pages under Wyoming go deeper on laws, local resources, and the data behind the risks named here.

The Yellowstone Caldera: an extremely low-probability, extremely high-consequence risk

Wyoming shares the Yellowstone region with Montana and Idaho, both already covered on this site through the 1959 Hebgen Lake earthquake and 1976 Teton Dam failure respectively, but Yellowstone’s own supervolcano deserves its own treatment. The annual probability of another caldera-forming eruption is approximately 1 in 730,000, roughly comparable to the odds of a large asteroid striking Earth, and the USGS reports no current indication that a major eruption is approaching. If one ever did occur, the areas of Wyoming, Montana, and Idaho closest to the caldera would face pyroclastic flows, while falling ash would affect a much wider area of the country. This isn’t a risk to lose sleep over day to day, but it’s a genuinely different category of hazard from anything else covered on this site: vanishingly unlikely, but catastrophic if it ever happened. See the Risks page for the full data.

The Blizzard of 1949: Wyoming’s worst storm on record

Starting January 2, 1949, a blizzard with winds of 65-80 mph dumped 20-30 inches of snow on Cheyenne within days, the first of what became two months of repeated snow and bitter cold across the state. It killed 12 people in Wyoming and required a rescue effort involving at least 10 state and federal agencies, from the U.S. Army to the National Park Service. See the Risks page for the full data.

What this means for how you use the rest of this manual

The manual’s Tier structure and the skill guides apply without modification. What’s different in Wyoming: extreme, sustained winter weather is a genuinely severe and historically proven risk here, not just an inconvenience, so this manual’s extended-outage and vehicle-emergency-kit guidance matters as much as anywhere covered on this site, and while the Yellowstone Caldera isn’t a near-term planning concern, it’s worth understanding why it’s mentioned at all: even an essentially negligible-probability hazard is worth a paragraph when the consequences would be regional or national in scale.

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