Idaho, 2002

Flash Flood and Damaging Winds in Idaho, July 22, 2002

July 22, 2002 · NWS BOI · 3 events in 2 counties and zones

Thunderstorms that developed in a very unstable airmass during the afternoon continued to intensify throughout the evening hours, training across parts of Ada County, through the Boise Foothills and into Boise County. Lightning strikes started numerous fires in the Boise Foothills.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

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The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
3

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.

What happened

The episode as NWS BOI wrote it up.

Thunderstorms that developed in a very unstable airmass during the afternoon continued to intensify throughout the evening hours, training across parts of Ada County, through the Boise Foothills and into Boise County. Lightning strikes started numerous fires in the Boise Foothills. Trees and power lines were blown down across west Boise and Horseshoe Bend. Over an inch and a half of rain fell within 20 minutes in the city of Boise and a section of Pierce Gulch Rd. was washed out in the Boise Foothills.

What forecasters said that day

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 Boise, ID wrote its last area forecast discussion before the first event at Jul 22, 8:30 PM MST, 15 minutes earlier.

Area forecast discussion, Jul 22, 8:30 PM MST, 15 minutes before
SOUTHWEST IDAHO/SOUTHEAST OREGON AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE IDAHO
930 PM MDT MON JUL 22 2002

SMALL AREA OF SEVERE WEATHER IN PROGRESS IN SOUTHWEST IDAHO AT THIS
TIME.  FIRE WEATHER WATCH CANCELLED FOR WETTER TYPE THUNDERSTORMS.

.BOI...SEE LATEST BOISVRBOI.

EGGER

The radar

The Boise radar (KCBX), 14 km away, was scanning. The volume nearest the first event began at 03:47 UTC.

Open the radar archive at this moment

Event by event

2 thunderstorm wind, 1 flash flood. Local standard time, as filed.

Thunderstorm Wind, Ada

When
July 22, 8:45 PM MST to 9:15 PM MST
Where
Ada County, Boise
Measured
50 kt (58 mph)
Reported by
LAW ENFORCEMENT
Coordinates
43.617, -116.217

Thunderstorm Wind, Boise

When
July 22, 9:15 PM MST to 9:45 PM MST
Where
Boise County, Horseshoe Bend
Measured
50 kt (58 mph)
Reported by
LAW ENFORCEMENT
Coordinates
43.917, -116.200

Flash Flood, Ada

When
July 22, 9:15 PM MST to 9:45 PM MST
Where
Ada County, 2 mi NW of Boise
Reported by
NWS STORM SURVEY
Coordinates
43.451, -116.241 (the zone’s center; the record gives no point)

What these are

Thunderstorm Wind
Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
Flash Flood
Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Idaho in 2002Every state in 2002This day in weather historyWarnings in Idaho, July 2002

Sources

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 2026-09-24. Each event’s entry at NCEI: 5309841, 5309842, 5309843.