High-Impact Weather and Climate Events

Slide blocked Highway 89, forcing Afton residents to detour 75 miles through Idaho to get to Jackson.

Virgin River Flood. "In 2010, a widespread, long duration rainfall event continued for 4 straight days. The North Fork Virgin River, which has a base flow rate of 100 cubic feet per second, rose to 6,000 cubic feet per second during this event. The Virgin River near the town of St. George recorded flows rising from 100 cubic feet per second to 25,000 cubic feet per second in a 24-hour period. Zion National Park was heavily damaged due to the flooding. The town of Washington also reported widespread flooding." - National Weather Service

The Fourmile Canyon Fire started after a month of extremely dry conditions, on a day with unusually strong winds for early September. Most of the 169 homes destroyed were burned on the first day of spread. About 6,500 acres were burned, and the city of Boulder itself was at risk on September 10.

A severe thunderstorm produced hail up to around golf-ball size in Gillette, causing extensive damage across the city. The storm moved generally from south to north through the city. The most heavily damaged areas were in the Westover Hills and Foothills subdivisions, as well as the downtown area. The hail damaged the roofs and windows of several thousand homes and buildings. Thousands of automobiles were damaged across the city.

A line of severe thunderstorms with damaging winds dropped large hail over a swath of the Denver metro area and spawned two weak tornadoes.

"A powerful tornado swept north-northwestward across Weld County and into Larimer County, carving a path of destruction, nearly 39 miles in length. The tornado, up to one-mile wide at times, initially touched down northeast of Platteville and finally lifted 6 miles west-northwest of Wellington. A tornado assessment in the aftermath of the tornado revealed extensive areas of damage. On the enhanced Fujita Scale there were pockets of EF3 damage, mainly near the Missile Silo Park Campground, and to businesses and homes in eastern Windsor. 
There was one fatality, and 78 injuries. One man was killed when he tried to escape the trailer park in his motor home. Preliminary estimates from FEMA indicated 850 homes were damaged, and nearly 300 homes were significantly damaged or destroyed. Privately insured damages totaled $147 million, and the Poudre Valley Rural Electric Associated reported $1 million of damage to electric transmission lines." - NWS

The Milford Flat Fire burned more than 363,000 acres, making it the largest wildfire in Utah history. The fire was ignited by dry thunderstorms and took place in cheatgrass, sagebrush, and pinyon-juniper stands. The fire destroyed rangeland in Millard and Beaver Counties killing cattle, burning four buildings and a cabin. Large stretches of I-15 were closed during the fire. Two people were killed in a fire-related motorcycle accident.

"Embankment North of Pueblo, Pueblo County, 2007: The area north of Pueblo was inundated by heavy rainfall in early May 2007. On the morning of May 7, an earthen embankment along Fountain Creek failed and 15 structures were flooded. The flooding was not a result of overtopping, but rather structural failure. This embankment was not a certified levee and was not identified on the effective FIRM." - CO Hazard Mitigation Plan 2018-2023

An EF3 tornado cut from south to north through Holly and the surrounding area, damaging or destroying 160 homes. Two residents of Holly were killed.

An upslope snowstorm first dropped 20+" on the Denver Metro area, then the focus shifted east and south, with totals of 12-36" in southeastern Colorado and 30-48" in the foothills and mountains of southern Colorado. Strong winds created enormous drifts and led to enormous loss of livestock.