This alert expired on 14 August 2026 at 01:00 UTC. It is kept here as a record.
It is the 2nd strongest of the 241 detections recorded within 20 km of this point since 15 March 2026. Another comparable one was recorded here earlier the same day. 2 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Flash Flood Warning issued August 13 at 5:33PM MDT until August 13 at 7:00PM MDT by NWS Denver CO
An estimated 2,364,891 people live within 50 km of this point.
Nearby, since 15 March 2026
- July 28, 2026 · score 52 · 5.4 km
- July 28, 2026 · score 52 · 10.2 km
- August 27, 2026 · score 58 · 14.7 km
How we know
Confirmed by 3 independent sources, including NOAA.
Our own score for this event is 52 out of 100, at 88 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 52 / 100 |
| Our confidence | 88% |
| Coordinates | 39.5064, -105.0199 |
| Nearest City | Highlands Ranch (6 km) |
| Population Exposed | 2.4M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-13T23:33:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Flash Flood Warning_noaa_urn:oid:2.49.0.1.840.0.0baaf12d3fed3274473a8229793550c1 |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Douglas, CO; Jefferson, CO; Western Arapahoe, CO; Denver, CO |
| Headline | Flash Flood Warning issued August 13 at 5:33PM MDT until August 13 at 7:00PM MDT by NWS Denver CO |
| Expires | 2026-08-13T19:00:00-06:00 |
| SenderName | NWS Denver CO |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.0baaf12d3fed3274473a8229793550c1ce134c61.001.1","noaa_urn:oid:2.49.0.1.840.0.8033c02a76c4f53eb5a850ca965da8b53d839465.001.1"] |
| Iem TypeSummary | H |
| Iem Magnitude | 1.25 |
| Iem Unit | Inch |
| Iem City | Centennial |
| Iem County | Arapahoe |
| Iem State | CO |
| Iem Wfo | BOU |
| Iem Remark | Report from mPING: Half Dollar (1.25 in.). |
| MergedSources | [{"id":"iem_H_39.620_-104.730_1786659900000","source":"iem","severity":"low","severityValue":25,"timestamp":1786659900000,"latitude":39.62,"longitude":-104.73},{"id":"iem_H_39.590_-104.870_1786659000000","source":"iem","severity":"low","severityValue":25,"timestamp":1786659000000,"latitude":39.59,"longitude":-104.87}] |
Safety Information
During flooding: never walk, swim, or drive through floodwaters. Six inches of moving water can knock you down, and one foot of water can sweep away a vehicle. Move to higher ground if waters rise. After flooding, avoid contact with floodwater which may contain sewage, chemicals, or debris. Follow local emergency service guidance.
Series begins 10 February 2026. Comparisons refer to that period only. Collection gap: 14-26 August 2026.
This data is aggregated algorithmically from scientific sources. Not a replacement for official emergency warnings.
Want to know when something happens near Highlands Ranch?
Calamity.live data shows a weather event with CalamityScore 52/100, near Highlands Ranch (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.