Calamity
MediumSevere WeatherCalamity Score: 48

Severe Weather near Sherman

GraysonUnited StatesNOAA

Right now

The most recent data we hold from NOAA arrived 4 minutes 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 27 May 2026 at 19:00 UTC. It is kept here as a record.

It is the 2nd strongest of the 21 detections recorded within 20 km of this point since 26 April 2026. Another comparable one was recorded here earlier the same day. 3 more were recorded here in the fortnight before it.

What the source measured

NOAA reported: Flash Flood Warning issued May 27 at 12:42PM CDT until May 27 at 2:00PM CDT by NWS Fort Worth TX

An estimated 568,455 people live within 50 km of this point.

Nearby, since 26 April 2026

How we know

Confirmed by 4 independent sources, including NOAA.

Our own score for this event is 48 out of 100, at 90 % confidence.

The score is ours, computed from intensity, exposed population and local history — not the source’s.

Computed under scoring rules v1. Rows carrying other versions were judged by different rules and are not directly comparable.

Event Data

TypeSevere Weather
SeverityMedium
Calamity Score (ours)48 / 100
Our confidence90%
Coordinates33.4574, -96.4579
Nearest CitySherman (25 km)
Population Exposed568.5K within 50 km
Impact Tiersignificant
Timestamp2026-05-27T17:42:00.000Z
Sourcehttps://api.weather.gov/alerts/merged_Flash Flood Warning_noaa_urn:oid:2.49.0.1.840.0.a1096d26f0c775067c1a15cdabc50df7

Score Breakdown

35
intensity
85
population
0
cascading
80
historical

Technical Details

EventFlash Flood Warning
UrgencyImmediate
CertaintyLikely
AreaDescFannin, TX; Grayson, TX; Collin, TX
HeadlineFlash Flood Warning issued May 27 at 12:42PM CDT until May 27 at 2:00PM CDT by NWS Fort Worth TX
Expires2026-05-27T14:00:00-05:00
SenderNameNWS Fort Worth TX
HasExactCoordstrue
MergedCount2
MergedIds["noaa_urn:oid:2.49.0.1.840.0.a1096d26f0c775067c1a15cdabc50df7a1714bdb.001.1","noaa_urn:oid:2.49.0.1.840.0.64708ab6ea98ceddb7e6b9f1e44f29801600302c.001.1"]
Iem TypeSummaryF
Iem City1 E Sachse
Iem CountyDallas
Iem StateTX
Iem WfoFWD
Iem RemarkEmergency Manager reported road closure of Sachse Rd at Country Club Rd due to high water.
MergedSources[{"id":"iem_F_33.380_-96.350_1779898500000","source":"iem","severity":"low","severityValue":25,"timestamp":1779898500000,"latitude":33.38,"longitude":-96.35},{"id":"iem_F_32.820_-96.470_1779897600000","source":"iem","severity":"low","severityValue":25,"timestamp":1779897600000,"latitude":32.82,"longitude":-96.47},{"id":"iem_F_32.980_-96.560_1779900480000","source":"iem","severity":"low","severityValue":25,"timestamp":1779900480000,"latitude":32.98,"longitude":-96.56}]

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.

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