High-Impact Weather and Climate Events

A severe storm with hurricane-force gusts affected Colorado and Wyoming over the course of a few days. This storm also brought the first tornado ever reported in Minnesota during the month of December, according to NOAA data.

CO: "The National Weather Service office in Pueblo recorded a 107 mph wind gust in Lamar shortly before 9 a.m." - CBS Denver

WY: "A National Weather Service peak wind report released Sunday morning showed a 118 mph gust blasted Clark, a small community in the northern part of the state, north of Cody." - Deseret News

"A powerful upper-level disturbance moving through the Rockies and Plains on June 6, 2020 sparked the development of a line of thunderstorms that brought widespread damaging winds from Utah and Colorado through northeastern Wyoming, western South Dakota, and southwestern North Dakota. Given the scope and intensity of the damaging winds, the storm system was classified as a "derecho" by the Storm Prediction Center.

Derechos are characterized by a several hundred mile-long swath of persistent severe wind gusts (58 mph or greater), with embedded wind gusts that are considered significantly severe (75 mph or greater). There is more information about derechos here." - National Weather Service

"Torrential rain fell and the charred land stripped of vegetation gave way, sending a rush of mud and boulders tumbling down steep canyon walls and onto highway I-70 near Glenwood Springs. Mudslides have become more frequent and intense since the Grizzly Creek Fire scorched about 50 square miles (130 square kilometers) in the summer of 2020." - PBS News Hour

"On the evening of 10 April 2013 (MDT) a massive landslide occurred at the Bingham Canyon copper mine near Salt Lake City, Utah, USA. The northeastern wall of the 970-m-deep pit collapsed in two distinct episodes that were each sudden, lasting ~90 seconds, but separated in time by ~1.5 hours. In total, ~65 million cubic meters of material was deposited, making the cumulative event likely the largest non-volcanic landslide to have occurred in North America in modern times. Fortunately, there were no fatalities or injuries." - GSA Today

The worst year of a statewide drought from 2000-2004. One of the worst droughts on record in the Upper Colorado River Basin. Low precipitation combined with above-average temperatures reduced available water. The statewide summer Palmer Drought Index was -6.1, the 2nd lowest on record. Dryland farmers reported low yields and a state of agricultural disaster was declared for drought and then grasshopper and Mormon cricket infestations. Costs are from 2002 and 2003 combined.

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

The Thorn Divide Complex began as 26 lightning-ignited fires. Before firefighters contained the fire, 14,874 acres and 2 buildings were burned. Supression costs were estimated at $7 million.

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.

The Jackson Canyon Wildfire was ignited by a lightning strike near Coal Mountain in Jackson Canyon. The fire burned 11,256 acres of land, including seven cabins, one barn, and two outbuildings before it was contained on August 23. The estimated cost of suppression was $3.8 million.

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.