Severe hailstorms, flash floods hit Boulder, Colorado

A severe hailstorm accompanied by flash floods hit Boulder, Colorado on June 12, 2023, causing damage and leading to emergency rescues.

The storm, which saw hailstones accumulate up to 2.54 – 5.08 cm (1 – 2 inches) in depth in downtown Boulder, was particularly severe due to the high volume of smaller stones up to 1.27 cm (0.5 inches) in diameter. The size of the largest stones was estimated to be slightly greater than 2.54 cm (1 inch). The aftermath of the storm saw several streets and creeks in Boulder flooded, leading to a significant disruption of daily life.

The National Weather Service (NWS) had issued a severe thunderstorm warning for parts of Colorado and New Mexico until 19:00 LT, cautioning about scattered wind gusts up to 112 km/h (70 mph), hail 5 cm (2 inches) in diameter, and the potential for tornadoes. Despite the warning, the city was ill-prepared for the volume of the hail that fell, leading to extensive flooding and the need for emergency rescue operations.

In the aftermath of the storm, crews worked tirelessly to clean up the deluge and repair roads after flooding in Boulder and Elbert counties. The Boulder fire service reported two people had to be rescued from flash flooding near Boulder Creek. Furthermore, several people near Goose Creek pond were reportedly stranded on an island due to water cutting through the bank. Boulder Fire-Rescue crews responded and helped get everyone to safety. No additional rescues were reported after this incident.

The Boulder police went on crash alert due to the high number of calls resulting from the heavy rainfall. According to Bernie Meier, a meteorologist for Boulder’s National Weather Service, the heaviest rainfall was recorded at an inch and a half at the Boulder County Justice Center, with overall rainfall between 25.4 cm to 50.8 cm (1 to 2 inches). The hail sizes were reported to be as large as a quarter in some parts of Boulder.

References:

¹ Boulder gets pounded with hail and flooding rain midday Monday – weather5280 – June 12, 2023

Featured image credit: Fox31 Denver (stillshot)