Tornadoes · United States · Idaho · 2000

F0 tornado, (Boi)Gowen Fld Boise, Idaho, August 3, 2000

This F0 tornado ran 0.1 miles across Ada County on August 3, 2000, touching down at 4:33 PM MDT and reaching 10 yards wide. It killed nobody.

The rating scale

Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. F040 to 72 mphthis tornado

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. F173 to 112 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. F2113 to 157 mph

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. F3158 to 206 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. F4207 to 260 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. F5261 to 318 mph

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unrated

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

The record

Rating
F0
Date
August 3, 2000
Touchdown
4:33 PM MDT (22:33 UTC)
Path length
0.1 miles (0.2 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
County
Ada County
Touchdown point
43.500, -116.220
Lift-off point
43.500, -116.220
Record number
130

What the Weather Service recorded

A series of thunderstorms moved though the Treasure Valley with 4 confirmed tornadoes in Ada county. One of these tornadoes touched down near Hidden Springs with damage limited to 2 large trees being uprooted. The path of the tornado was 10 yards wide and less than one-tenth of a mile in length. Another touched down near the intersection of Lake Hazel Road and 5 Mile Road. Damage was confined to one home where a flag pole was bent in half and a 2x4 was imbedded in the outer wall of the home. No injuries occurred and damage estimates were unavailable. The other 2 tornadoes touched down briefly south of the airport in open country. These were observed by off-duty NWS meteorologists and a trained spotter. These tornadoes caused no damage.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

Issued (UTC)ExpiredProductOffice
22:40 UTC23:15 UTCTornado WarningBOI

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The forecast that day

The Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 20:13 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The air that afternoon

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Boise Airport, ID (KBOI), 12:00Z

10.6 hours before the tornado, 8 km from the path. August 3, 2000.

Skew-T log-pSkew-T log-p diagram, Boise Airport, ID at 12:00Z on 2000-08-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -88752, lifted condensation level 3765 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Boise Airport, ID at 12:00Z on 2000-08-03The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 54 square meters per square second, 0 to 6 km bulk shear 32 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
-88752 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
3765 m above ground
0-6 km bulk shear
32 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
54 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.0 K/km

Open this sounding in Storm Lab

Boise Airport, ID (KBOI), 00:00Z

1.4 hours after it, 8 km from the path. August 4, 2000.

Skew-T log-pSkew-T log-p diagram, Boise Airport, ID at 00:00Z on 2000-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 20 joules per kilogram, CIN -230, lifted condensation level 3733 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Boise Airport, ID at 00:00Z on 2000-08-04The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 186 square meters per square second, 0 to 6 km bulk shear 39 knots.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
20 J/kg
Mixed-layer CIN
-230 J/kg
Surface CAPE
1337 J/kg
Mixed-layer LCL
3733 m above ground
0-6 km bulk shear
39 kt
0-1 km bulk shear
16 kt
0-1 km storm-relative helicity
186 m²/s²
0-3 km storm-relative helicity
234 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1
0-3 km lapse rate
8.5 K/km

Open this sounding in Storm Lab

The surface observations

Boise Municipal (BOI), 8 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
20:56 UTC994680° 9 kt141010.8
21:56 UTC1014520° 7 kt1010.2
22:46 UTC89.651.8220° 23 kt321010.8TS HZ
22:56 UTC8653230° 26 kt371011.2-TSRA
23:00 UTC84.255.4210° 27 kt371011.2-TSRA
23:07 UTC87.853.6210° 13 kt331012.2-TSRA
23:32 UTC91.453.610° 4 kt1009.8-TSRA
23:42 UTC93.253.640° 9 kt141009.8
23:56 UTC955040° 9 kt1009.8

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Boise radar (KCBX), 2 km away, was scanning. The volume nearest the touchdown began at 22:38 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

This ground now

The live radar over the trackEvery 2000 tornado in IdahoEvery tornado in Idaho since 1950Warnings in force in Idaho nowThe forecast where you are

The other tornadoes of August 3, 2000

4 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 32:45 PM EDTF0Charleston, SC0.120
August 34:15 PM MDTF0Ada, ID0.00
August 34:48 PM MDTF0Ada, ID0.110
August 34:51 PM MDTF0Ada, ID0.110

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.