Tornadoes · United States · Colorado · 2020

EF0 tornado, Akron, Colorado, August 15, 2020

This EF0 tornado ran 0.0 miles across Washington County on August 15, 2020, touching down at 5:52 PM MDT and reaching 50 yards wide. It killed nobody.

The rating scale

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

  1. EF065 to 85 mphthis tornado

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

  2. EF186 to 110 mph

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

  3. EF2111 to 135 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. EF3136 to 165 mph

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

  5. EF4166 to 200 mph

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

  6. EF5over 200 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
EF0
Date
August 15, 2020
Touchdown
5:52 PM MDT (23:52 UTC)
Lifted
5:55 PM MDT (23:55 UTC)
On the ground
3 minutes
Path length
0.0 miles (0.0 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Washington County
Touchdown point
40.050, -103.350
Lift-off point
40.050, -103.350
Record number
2008151752-01

What the Weather Service recorded

Severe thunderstorms produced large hail, ranging in size from quarters to tennis balls. Three brief landspout tornadoes developed in open country. No damage was observed.

A weak landspout touched down briefly in open country. No damage was observed.

A weak landspout touched down briefly in open country. No damage was observed.

A weak landspout tornado down briefly in open country. No damage was observed.

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
23:15 UTC23:45 UTCSevere Thunderstorm WarningBOU
23:39 UTC00:15 UTCSevere Thunderstorm WarningBOU
00:03 UTC00:30 UTCTornado WarningBOU

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 Marginal Risk. The outlook in force was issued at 19:54 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.

Denver, CO (KDNR), 12:00Z

11.9 hours before the tornado, 22 km from the path. August 15, 2020.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 12:00Z on 2020-08-15Temperature 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 -2207, lifted condensation level 2130 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 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, Denver, CO at 12:00Z on 2020-08-15The 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 43 square meters per square second, 0 to 6 km bulk shear 22 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
0 J/kg
Mixed-layer CIN
-2207 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
2130 m above ground
0-6 km bulk shear
22 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
43 m²/s²
0-3 km storm-relative helicity
57 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.9 K/km

Open this sounding in Storm Lab

Denver, CO (KDNR), 00:00Z

0.1 hours after it, 22 km from the path. August 16, 2020.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 00:00Z on 2020-08-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 76 joules per kilogram, CIN -105, lifted condensation level 3509 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, Denver, CO at 00:00Z on 2020-08-16The 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 1 square meters per square second, 0 to 6 km bulk shear 24 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
76 J/kg
Mixed-layer CIN
-105 J/kg
Surface CAPE
11 J/kg
Mixed-layer LCL
3509 m above ground
0-6 km bulk shear
24 kt
0-1 km bulk shear
3 kt
0-1 km storm-relative helicity
1 m²/s²
0-3 km storm-relative helicity
46 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0
0-3 km lapse rate
9.2 K/km

Open this sounding in Storm Lab

The surface observations

Akron/Washington Co (AKO), 18 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
21:35 UTC140° 15 kt1020.7
21:40 UTC130° 15 kt1020.3
21:45 UTC 15 kt1020.7
21:50 UTC140° 11 kt191020.7
21:53 UTC9060120° 10 kt221020.3
22:00 UTC130° 11 kt1020.3
22:05 UTC140° 16 kt211020.3
22:10 UTC120° 13 kt1020.3
22:15 UTC130° 11 kt1020.3
22:20 UTC 15 kt1020.3
22:25 UTC130° 17 kt221020.3
22:30 UTC140° 14 kt221020.3
22:35 UTC130° 15 kt211020.3
22:45 UTC 21 kt291019.6
22:50 UTC 21 kt1019.6
22:53 UTC8763120° 24 kt301019.6VCTS
22:55 UTC110° 27 kt331020
23:00 UTC110° 26 kt311020.3
23:05 UTC8463110° 23 kt351020.3TS
23:15 UTC110° 19 kt231020.7-RA
23:20 UTC120° 18 kt1020.3
23:21 UTC8165120° 17 kt1020.3VCTS
23:25 UTC110° 16 kt221021-RA
23:30 UTC100° 14 kt1021.3-RA
23:34 UTC796780° 11 kt231021.3-TSRA
23:35 UTC90° 11 kt1021.3-RA
23:40 UTC110° 15 kt211021-RA
23:45 UTC110° 18 kt221020.7-RA
23:53 UTC7868110° 13 kt241021-TSRA
23:55 UTC110° 13 kt-RA
00:00 UTC7868110° 14 kt1021VCTS
00:05 UTC110° 11 kt1021
00:10 UTC120° 13 kt1021
00:15 UTC8066120° 13 kt1021
00:30 UTC100° 13 kt1021
00:35 UTC110° 14 kt1021
00:40 UTC110° 13 kt181021
00:45 UTC120° 13 kt1021
00:50 UTC130° 13 kt1021
00:53 UTC8064140° 13 kt1021
01:00 UTC130° 11 kt1021
01:05 UTC130° 13 kt1021
01:10 UTC130° 11 kt1021
01:15 UTC120° 10 kt151021
01:20 UTC120° 11 kt1021.3

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

The radar

The Denver radar (KFTG), 106 km away, was scanning. The volume nearest the touchdown began at 23:52 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.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
23:15 UTCHAIL 1.254 Wnw AkronWashington, CO
23:36 UTCHAIL 25 Sw AkronWashington, CO
23:38 UTCTORNADO5 Sw AkronWashington, COWEAK LANDSPOUT TORNADO LASTED FROM 533 PM UNTIL 538 PM.
23:40 UTCHAIL 2.58 Sw AkronWashington, CO
23:47 UTCHAIL 25 Se MidwayWashington, CO
23:48 UTCTORNADO9 S MidwayWashington, COLANDSPOUT TORNADO.
23:55 UTCTORNADO10 Nw ElbaWashington, COLANDSPOUT TORNADO LASTED 2 TO 3 MINUTES.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2020 tornado in ColoradoEvery tornado in Colorado since 1950Warnings in force in Colorado nowThe forecast where you are

The other tornadoes of August 15, 2020

6 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 151:30 PM PDTEF1Lassen, CA0.4137
August 152:04 PM PDTEF1Lassen, CA0.120
August 152:41 PM PDTUnratedLassen, CA3.2156
August 154:30 PM MDTEF0Bernalillo, NM0.020
August 155:33 PM MDTEF0Washington, CO0.050
August 155:47 PM MDTEF0Washington, CO0.050

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.