Tornadoes · United States · Idaho · 2000

F0 tornado, Kuna, Idaho, July 18, 2000

This F0 tornado ran 0.1 miles across Ada County on July 18, 2000, touching down at 6:57 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
July 18, 2000
Touchdown
6:57 PM MDT (00:57 UTC)
Path length
0.1 miles (0.2 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
County
Ada County
Touchdown point
43.450, -116.450
Lift-off point
43.450, -116.450
Record number
436

What the Weather Service recorded

Monsoonal moisture moving into Southeast Oregon and Southwest Idaho, coupled with a weak area of low pressure, initiated afternoon covection in Southeast Oregon. As the line of thunderstorms moved into Southwest Idaho, a thunderstorm outflow boundary collided with another strong cell in southern Ada county, generating a short-lived tornado. Three storm spotters independently witnessed the evolution and touchdown of the tornado, which was also confirmed by a follow-up storm survey. The tornado touched down on an unpopulated, barren butte and no injuries or damages were sustained. Prior to the tornado, high winds ripped through Canyon county with gusts to 60 mph. An old growth tree was snapped and several power lines were felled.

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

The warnings

0 minutes of warning. NWS BOI issued a tornado warning for this county at 00:57 UTC, 0 minutes before the tornado touched down, in force until 01:30 UTC.

Issued (UTC)ExpiredProductOffice
00:57 UTC01:30 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 21:28 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), 00:00Z

1.0 hours before the tornado, 24 km from the path. July 19, 2000.

Skew-T log-pSkew-T log-p diagram, Boise Airport, ID at 00:00Z on 2000-07-19Temperature 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 -88432, lifted condensation level 3664 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 00:00Z on 2000-07-19The 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 18 square meters per square second, 0 to 6 km bulk shear 10 knots.1939Sfc1 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
-88432 J/kg
Surface CAPE
770 J/kg
Mixed-layer LCL
3664 m above ground
0-6 km bulk shear
10 kt
0-1 km bulk shear
4 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
53 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
9.6 K/km

Open this sounding in Storm Lab

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

11.0 hours after it, 24 km from the path. July 19, 2000.

Skew-T log-pSkew-T log-p diagram, Boise Airport, ID at 12:00Z on 2000-07-19Temperature 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 -88693, lifted condensation level 2590 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 2000-07-19The 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 66 square meters per square second, 0 to 6 km bulk shear 23 knots.1939Sfc1 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
-88693 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
2590 m above ground
0-6 km bulk shear
23 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
66 m²/s²
0-3 km storm-relative helicity
77 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.5 K/km

Open this sounding in Storm Lab

The surface observations

Boise Municipal (BOI), 21 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
23:56 UTC8746 5 kt1018.6
00:56 UTC7854270° 15 kt211019-RA
01:56 UTC7055310° 11 kt1020.7
02:20 UTC69.855.440° 10 kt1020.3
02:56 UTC745070° 13 kt201019.3-RA

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

The radar

The Boise radar (KCBX), 18 km away, was scanning. The volume nearest the touchdown began at 00:55 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 July 18, 2000

9 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
July 181:30 PM EDTF0Levy, FL0.10
July 182:00 PM EDTF1Oxford, ME0.5150
July 183:15 PM CDTF0Plaquemines Parish, LA0.120$1,000
July 185:55 PM CDTF1Montgomery, MO4.050$70,000
July 186:50 PM CDTF0Macoupin, IL0.140
July 186:58 PM CDTF0Lincoln, MO0.140
July 187:30 PM CDTF0Jersey, IL0.140
July 187:35 PM CDTF0Lincoln, MO0.140
July 188:10 PM CDTF0Macoupin, IL0.140

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.