Clouds dissipated in the wake of a broad upper level trough which led to strong radiational cooling across western Colorado. This led to subfreezing temperatures in many of the lower valleys where vegetation was sensitive to damage.
Every event with a place to put it; 6 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS GJT wrote it up.
Clouds dissipated in the wake of a broad upper level trough which led to strong radiational cooling across western Colorado. This led to subfreezing temperatures in many of the lower valleys where vegetation was sensitive to damage.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Grand Junction, CO wrote its last area forecast discussion before the first event at May 23, 4:35 PM MST, 6 hours 25 minutes earlier.
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Service Notice</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<main class="wrap">
<section class="card" role="status" aria-live="polite">
<div class="status" id="status">Temporary Notice</div>
<h1 id="headline">This service is currently unavailable.</h1>
<p id="message1">
The site you requested is temporarily down for maintenance or an unexpected outage.
</p>
<p id="message2">
Please try again in a few minutes.
</p>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html><!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Service Notice</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<main class="wrap">
<section class="card" role="status" aria-live="polite">
<div class="status" id="status">Temporary Notice</div>
<h1 id="headline">This service is currently unavailable.</h1>
<p id="message1">
The site you requested is temporarily down for maintenance or an unexpected outage.
</p>
<p id="message2">
Please try again in a few minutes.
</p>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>The national radar mosaic for the moment the first event began.
6 frost/freeze. Local standard time, as filed.
Overnight lows ranged from 28 to 32 degrees with a low temperature of 28 degrees recorded at the Cortez Municipal Airport.
Overnight lows ranged from 28 to 32 degrees with a low temperature of 28 degrees recorded at the Craig-Moffat Airport.
Overnight lows ranged from 28 to 32 degrees with a low temperature of 28 degrees recorded at the Durango-La Plata County Airport.
Overnight lows ranged from 25 to 30 degrees with a low temperature of 28 degrees recorded at the Eagle County Regional Airport.
Overnight lows ranged from 24 to 29 degrees with a low temperature of 29 degrees recorded at the Steamboat Springs/Bob Adams Field Airport.
Overnight lows ranged from 30 to 32 degrees.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2021Every state in 2021This day in weather historyWarnings in Colorado, May 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 950500, 950499, 950501, 950503, 950504, 950502.