Right now
The most recent data we hold from NOAA arrived 1 minute ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
Nothing else has been detected within 20 km in the last 24 hours.
This alert expired on 22 July 2026 at 01:30 UTC. It is kept here as a record.
It is the 77th strongest of the 161 detections recorded within 20 km of this point since 12 March 2026. Another comparable one was recorded here earlier the same day. 4 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Flash Flood Warning issued July 21 at 6:21PM EDT until July 21 at 9:30PM EDT by NWS Baltimore MD/Washington DC
Urban PEI: 3,683,889 within a heuristic 50 km radius; not unique people.
Nearby, since 12 March 2026
- July 21, 2026 · score 46 · 0.1 km
- July 4, 2026 · score 52 · 5.0 km
- June 6, 2026 · score 52 · 6.3 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 46 out of 100.
This is our versioned heuristic index, not source severity or a calibrated probability. Urban PEI does not count unique people.
Computed under scoring rules v1. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 46 / 100 |
| Legacy data-support index | 0.79/1 |
| Coordinates | 40.2557, -75.1555 |
| Nearest City | Lansdale (11 km) |
| Urban exposure index (PEI) | 3.7M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-21T22:21:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Flash Flood Warning_noaa_urn:oid:2.49.0.1.840.0.538111e23e8c0e840ff6289c8287f76b |
Physical priority index · v1. Heuristic priority, not calibrated probability, predictive accuracy or damage. The legacy data-support index combines assigned source support and field availability. Urban PEI is distance-weighted and does not count unique people; zero does not establish that nobody is present. Model cards.
Source and revision timeline
Source: noaa. Occurrence: 2026-07-21T22:21:00.000Z.
First archived: 2026-07-21T22:39:00.148Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Anne Arundel, MD; Baltimore, MD; Baltimore City, MD; New Castle, DE; Goochland, VA; Hanover, VA; Henrico, VA; City of Richmond, VA and 6 more areas |
| Headline | Flash Flood Warning issued July 21 at 6:21PM EDT until July 21 at 9:30PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-07-21T21:30:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 9 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.538111e23e8c0e840ff6289c8287f76bf29c6b4c.001.1","noaa_urn:oid:2.49.0.1.840.0.ce77037efb5c6499a996faa88d3316882034626f.002.1","noaa_urn:oid:2.49.0.1.840.0.c91614e0b002e5d1ef8b9b33c8b40446f5a7ee31.001.1","noaa_urn:oid:2.49.0.1.840.0.e5c016fdb5b2cf67375696d929c58c505fc7e19c.001.1","noaa_urn:oid:2.49.0.1.840.0.715d754a508814328cffb6ac641c0665e9bec213.001.1","noaa_urn:oid:2.49.0.1.840.0.c312c2c99bf28cbcb3618dbc94a4238c1a4096dd.001.1","noaa_urn:oid:2.49.0.1.840.0.9e45ce87e50e91fcf54645bbe20d9d8eabfec984.001.1","noaa_urn:oid:2.49.0.1.840.0.644fa1ebdd545b023b48b7488dd4c072f9d14eeb.001.1","noaa_urn:oid:2.49.0.1.840.0.f69cd042ad8167a938448a9c4847aa09be832043.001.1"] |
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 8 March 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.
Review the area, threshold and delivery channel in your account.
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