High-Impact Weather and Climate Events

A record-breaking blizzard developed across portions of Colorado Wyoming and Nebraska on March 13th and 14th, 2019. The record-setting area of low pressure reached a minimum central pressure of 971 mb across eastern Colorado. This set an all-time pressure record for the state.

La Junta recorded its strongest wind gust during the bomb cyclone — an 88 mph gust. An 80 mph gust recorded at Denver International Airport during the heart of the storm made it the strongest non-thunderstorm wind gust recorded there. Winds reached a record 96 mph in Colorado Springs.

The "Bomb" Cyclone rapidly intensified from the evening of the 12th through the morning of the 13th. This rapid intensification brought extremely strong winds and very strong dynamic lift which generated extremely heavy snowfall over Wyoming and Nebraska (www.weather.gov). Subsequently, the blizzard resulted in widespread flooding across the US (www.cnn.com), affecting many states.

Severe thunderstorms in late afternoon produced giant hail up to baseball size (2.75") that pummeled a swath extending from Golden northeast through north Denver. Hail size exceeded 2" across Denver and Jefferson Counties and damaged over 50,000 homes, over 100,000 vehicles, and many businesses. Colorado Mills Mall in Lakewood was closed for 6 months to repair roof and interior damage. NOAA officially estimated damages of $2.5B, or $3.9B in 2022 dollars, which is higher than an early estimate of $1.4B by RMIIA that was widely reported. In either case, it was the most costly hailstorm in Colorado history.

A near-stationary weather system funneled copious subtropical moisture into the Front Range, leading to one-week rainfall totals of 10-18" over a large area. Creeks and rivers from the Wyoming border to Colorado Springs flooded, with the worst flooding on the Big Thompson River, Little Thompson River, St. Vrain Creek, Lefthand Creek, and Coal Creek. Over 20,000 homes were damaged or destroyed. Incredible and widespread damage to civil infrastructure (roads, bridges, water conveyance and treatment) on the Front Range.

The worst year of a multi-year drought (2000-2002 for eastern Colorado, and 2000-2004 for western Colorado). One of the driest water years on record in all parts of the state, with very low snowpacks, extremely low runoff, many large wildfires, and severe agricultural impacts. The statewide summer Palmer Drought Index was -8.7, the lowest on record.

Part of NCDC's billion-dollar disaster list. In total, the estimated damage the severe storms and hail caused in CO is over $1B.

"Unusual overnight severe weather hit the metro area Wednesday into Thursday, bringing lightning, thunder, heavy rain, hail and flooding to much of the region. Despite several Tornado Warnings, there were no confirmed tornado touchdowns with the round of late night storms. Hail hit the southern and western parts of metro Denver especially hard. Several inches were on the ground Thursday in places such as Castle Rock, Parker and Highlands Ranch." - FOX31

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 supercell thunderstorm traveled from Estes Park to Colorado Springs, passing directly over Denver with large hail. Thousands of roofs and cars were damaged. At the time, the costliest hailstorm in US history.

The East Troublesome Fire is the second-largest wildfire in Colorado history as of 2020.

"The East Troublesome Fire was reported on the afternoon of October 14. The origination point was northeast of Kremmling in Grand County, Colo. on the Arapaho National Forest. The cause is still under investigation. Within three days, high winds and low humidity allowed the fire to spread to over 10,000 acres. The direction of fire spread threatened State Highway 125 and forced the closure of the road and mandatory evacuation of approximately 90 homes by October 17.

Between Oct. 20-23, the fire spread increased dramatically with 24-hour increases of around 18,000 to 87,000 acres during the four-day run. The peak fire spread of 87,093 acres occurred between late afternoon on Oct. 21 and the early afternoon of Oct. 22. The size of the fire exploded from 18,550 acres to 187,964 acres during this period. The fire crossed Highway 125 on the afternoon of Oct. 21 and spread eastward into the Rocky Mountain National Park on Oct. 22, crossing the Continental Divide and reaching the western edge of Estes Park on Oct. 23.

The fire was fueled by wide-spread drought, numerous dead and down beetle-killed trees, red flag weather conditions created by high winds and dry conditions, and poor humidity recovery overnight. The combination of these factors led to unprecedented, wind-driven, active fire behavior with rapid spread during the overnight hours. During this period the area north of US Highway 40 from near Granby and extending eastward to Grand Lake and Estes Park had over 7,000 structures threatened, and a population of over 35,000 placed under a mandatory evacuation.

A winter storm from Saturday, Oct. 24 through the morning of Oct. 26 brought very cold temperatures, precipitation in the form of snow and lighter winds, resulting in a dramatic drop in fire behavior with smoldering and reduced fire spread on both sides of the Continental Divide. Over this 3-day period, fire growth fell to a total of around 4,500 acres for a total of 192,457 acres. From that point forward, fire activity remained minimal with little change in area and a final total acreage of 193,812. The fire was declared contained on Nov. 30, 2020." - InciWeb

By some measures, this is still the most costly and destructive flood event in Colorado history. Intense thunderstorms near Castle Rock dropped over 14" of rain in several hours, causing extreme flooding on Plum Creek, Cherry Creek and the South Platte River. The flood zone included two-thirds of Denver's industrial area. The Purgatoire River and lower Arkansas River also experienced severe flooding; 11" of rain fell at Holly and over 15" near Lamar in one day.

The Marshall Fire is the most destructive wildfire in Colorado history, in terms of cost and structures lost, as of 2021.

See our Marshall Fire Briefing for an overview of the event. The briefing represents our state of knowledge as it exists January 13, 2022 and is provided as a service to place the disastrous fire into a climate and human context.