Weather alerts in Colorado, 2016
3,057 weather alerts in 2016, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered any part of the state, so the counties below add up to more than the state.
Weather alerts by county
Each county as a circle sized by its count in 2016. Tap one for its archive.
- Alerts
- 3,057
- Warnings
- 1,170
- Watches
- 178
- Advisories
- 363
- Busiest month
- July871 alerts
- Busiest day
- July 8, 201695 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
22 of 89 tornado warnings covering Colorado in 2016 had a tornado report inside them; 39 of 62 tornado reports fell inside a warning, on average 14 minutes after it went out.
Colorado, 2016
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 89 | 22 | 75% | 62 | 63% | 14 min |
| Severe thunderstorm warnings | 795 | 241 | 70% | 571 | 77% | 20 min |
| Flash flood warnings | 79 | 13 | 84% | 42 | 62% | 49 min |
Each office's whole area, 2016
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Goodland, KS: tornado warnings | 82 | 20 | 76% | 44 | 66% | 15 min |
| NWS Goodland, KS: severe thunderstorm warnings | 595 | 158 | 73% | 350 | 78% | 24 min |
| NWS Goodland, KS: flash flood warnings | 82 | 18 | 78% | 37 | 65% | 105 min |
| NWS Grand Junction, CO: severe thunderstorm warnings | 13 | 3 | 77% | 19 | 26% | 7 min |
| NWS Grand Junction, CO: flash flood warnings | 14 | 1 | 93% | 17 | 6% | 95 min |
| NWS Pueblo, CO: tornado warnings | 20 | 6 | 70% | 13 | 69% | 20 min |
| NWS Pueblo, CO: severe thunderstorm warnings | 293 | 92 | 69% | 239 | 83% | 20 min |
| NWS Pueblo, CO: flash flood warnings | 37 | 6 | 84% | 21 | 90% | 40 min |
| NWS Denver/Boulder, CO: tornado warnings | 30 | 6 | 80% | 20 | 60% | 12 min |
| NWS Denver/Boulder, CO: severe thunderstorm warnings | 259 | 94 | 64% | 230 | 72% | 19 min |
| NWS Denver/Boulder, CO: flash flood warnings | 8 | 1 | 88% | 3 | 33% | 18 min |
An office's figures cover every county it serves, including across state lines.
Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.
The alerts
3,057 alerts are too many to list on one page. Narrow it to a product above, to a month in the chart, or to a county.
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
By county
Every county with at least one alert. A county page lists each alert that covered it.
- El Paso County353
- Kit Carson County351
- Yuma County346
- Cheyenne County289
- Pueblo County245
- Baca County237
- Las Animas County215
- Kiowa County209
- Weld County191
- Prowers County189
- Bent County188
- Washington County168
- Huerfano County163
- Lincoln County150
- Phillips County145
- Crowley County144
- Fremont County141
- Elbert County141
- Otero County141
- Arapahoe County140
- Adams County139
- Moffat County136
- Douglas County134
- Logan County132
- Garfield County130
- Mesa County130
- Morgan County130
- Rio Blanco County126
- Jefferson County123
- Teller County121
- Larimer County119
- Boulder County118
- Sedgwick County113
- Montrose County112
- Saguache County111
- San Miguel County107
- Custer County98
- Routt County96
- Park County94
- Denver County92
24 more counties
- La Plata County91
- Dolores County88
- Montezuma County88
- Costilla County83
- Delta County83
- Gunnison County83
- Eagle County83
- Clear Creek County82
- Gilpin County82
- Pitkin County78
- Broomfield County74
- Grand County74
- Rio Grande County71
- Jackson County70
- Archuleta County69
- Alamosa County69
- Summit County68
- Chaffee County67
- Conejos County63
- Ouray County62
- Hinsdale County55
- Lake County49
- San Juan County48
- Mineral County41
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20152017
Sources
National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.