Tornadoes · United States · Oregon · 2010

EF2 tornado, Aumsville to Shaw, Oregon, December 14, 2010

From Aumsville to Shaw, this EF2 tornado ran 5.0 miles across Marion County on December 14, 2010, touching down at 7:40 PM PST and reaching 150 yards wide. It killed nobody and injured 2, and did $1.2 million of property damage.

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 mph

    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 mphthis tornado

    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
EF2
Date
December 14, 2010
Touchdown
7:40 PM PST (03:40 UTC)
Lifted
7:50 PM PST (03:50 UTC)
On the ground
10 minutes
Path length
5.0 miles (8.0 km)
Path width
150 yards (137 m)
Deaths
0
Injuries
2
Property damage
$1.2 million
County
Marion County
Touchdown point
44.840, -122.879
Lift-off point
44.864, -122.835
Record number
1012142140-01

What the Weather Service recorded

A strong cold pool of air aloft produced a very unstable airmass over western Oregon. |A vigorous low pressure center was just off the Washington Coast with a surface trough moving through western Oregon. This trough served as a focus for thunderstorms during the day. One of these thunderstorms produced a tornado that wreaked havoc on the community of Aumsville.

On December 14th at 11:40 AM PST, a tornado with an Enhanced Fujita Scale rating of EF2 moved northeast across the community of Aumsville, Oregon. The estimated length of the tornado path was 5 miles with a width of 150 yards. There were two minor injuries, fifty structures damaged, more than thirty large trees blown down or snapped off, five sheds damaged and two semi-trailers tipped over. The estimated value of the damage was $1.2 million.

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
19:53 UTC20:11 UTCSevere Thunderstorm WarningPQR
20:02 UTC20:30 UTCTornado WarningPQR
00:25 UTC23:31 UTCFlood WarningPQR

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 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.

Salem/Mcnary, OR (KSLE), 00:00Z

3.7 hours before the tornado, 14 km from the path. December 15, 2010.

Skew-T log-pSkew-T log-p diagram, Salem/Mcnary, OR at 00:00Z on 2010-12-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 170 joules per kilogram, CIN -16, lifted condensation level 816 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, Salem/Mcnary, OR at 00:00Z on 2010-12-15The 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 157 square meters per square second, 0 to 6 km bulk shear 47 knots.1939587897117Sfc1 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
170 J/kg
Mixed-layer CIN
-16 J/kg
Surface CAPE
520 J/kg
Mixed-layer LCL
816 m above ground
0-6 km bulk shear
47 kt
0-1 km bulk shear
24 kt
0-1 km storm-relative helicity
157 m²/s²
0-3 km storm-relative helicity
213 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.6
0-3 km lapse rate
7.7 K/km

Open this sounding in Storm Lab

Salem/Mcnary, OR (KSLE), 12:00Z

8.3 hours after it, 14 km from the path. December 15, 2010.

Skew-T log-pSkew-T log-p diagram, Salem/Mcnary, OR at 12:00Z on 2010-12-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 27 joules per kilogram, CIN -16, lifted condensation level 603 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, Salem/Mcnary, OR at 12:00Z on 2010-12-15The 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 146 square meters per square second, 0 to 6 km bulk shear 42 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
27 J/kg
Mixed-layer CIN
-16 J/kg
Surface CAPE
22 J/kg
Mixed-layer LCL
603 m above ground
0-6 km bulk shear
42 kt
0-1 km bulk shear
20 kt
0-1 km storm-relative helicity
146 m²/s²
0-3 km storm-relative helicity
147 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.9 K/km

Open this sounding in Storm Lab

The radar

The Portland,OR radar (KRTX), 96 km away, was scanning. The volume nearest the touchdown began at 03:38 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 2010 tornado in OregonEvery tornado in Oregon since 1950Warnings in force in Oregon nowThe forecast where you are

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.