Tornado Outbreak Strikes Northern Arizona
October 6, 2010

Updated October 12, 2010 at 500 PM MST.

Lastest update includes: Total number of confirmed tornadoes is now 8 (Garjon Tank tornado and Cordes Junction tornado have been added). Map has been updated to include additional tornado tracks. A synopotic overview of the event is now included. See update log at bottom of the page for a complete history of updates.

If you are a resident or visitor of northern Arizona, and if you experienced any wind or tornado damage related to the storms on October 6, 2010, please send your stories and pictures to the National Weather Service Flagstaff office by e-mail to In addition, please e-mail us if you observed any large hail. Pictures to go along with your reports are always greatly appreciated. With any reports you send us, it is important to include the exact location of the wind or tornado damage or hail, along with details of the time that it occurred. Please let us know if we can include your pictures in our storm reports. Thank you!

A major severe weather event struck northern Arizona early on Wednesday, October 6, 2010. With at least 8 confirmed tornadoes, this event will go down in history as the most tornadoes to strike the state in a single day. Not only was the number of tornadoes impressive, but several of the tornadoes were damaging and long tracked events. One of the tornadoes had a nearly continuous path exceeding 30 miles, while another tornado southeast of Tuba City was violent enough for a preliminary rating of EF-3 on the Enhanced Fujita scale. Highlighted below is a meteorological summary of the outbreak.

On October 5th (the day prior to the tornado outbreak), a strong low pressure system in southern California forced strong southerly winds across the state, allowing rich moisture to move northward into the state from Mexico. Skies across much of northern Arizona were mostly cloudy, however, skies were clear across the southern half of the state. As the deserts warmed during afternoon, the atmosphere became very unstable and storms erupted across the state, most notably with several severe storms striking the Phoenix metro area. These storms continued to develop after nightfall and race northwards across northern Arizona.

Visible Satellite Loop from 4:00-4:30 PM MST Tuesday October 5, 2010

visible satellite loop

Shortly after midnight, new storms began to develop along the I-17 corridor. At this time, the low in southern California inched closer, and a strong short wave evident in the water vapor imagery approached from the west. The wind shear (change in wind direction and speed with height) become very strong across northern Arizona, veering from southwesterly in the mid levels, to southeasterly in the low levels. It was at this time that the environment became increasingly favorable for tornadic thunderstorms, with the first tornado touchdown near Blue Ridge at approximately 1:58 am MST.

Water Vapor Loop from 3:15-5:30 AM MST Wednesday October 6, 2010

water vapor beginning around 10Z

NWS Flagstaff Radar Loop 1:00-5:00 AM MST (8:00-12:00Z) Wednesday October 6, 2010

Radar from 1am-5am

As the early morning progressed, more storms developed and moved quickly northward, becoming supercells with strong rotational signatures on radar. The low pressure system driving the thunderstorm activity was not moving significantly, and remained west of the Arizona border. The strong southerly flow, and atmospheric forcing in place caused severe and tornadic storms to continually redevelop over the same areas (a highly unusual event!). The 12z (5 AM MST) weather balloon launch from Bellemont indicated that despite being fairly cool with surface temperatures near 50F, the atmosphere was quite unstable due to the very cold temperatures aloft. Strong wind shear was present in the profile, causing the storms which formed to rotate, and engender the tornadic production. The very cold temperatures in the profile (-14C, or 7F at around 19,000 ft) aided in hail production within the storms.

Upper Air Sounding from Bellemont, AZ at 5 AM MST Wednesday October 6, 2010

12Z FGZ sounding

NWS Flagstaff Radar Loop 5:00-9:00 AM MST (12:00-16:00Z) Wednesday October 6, 2010

Radar from 5am-9am

By mid-morning, strong storms continued across the Interstate-17 corridor northward towards Utah, with new development across the little Colorado River Valley east of Flagstaff, and south of Tuba City. The lead shortwave forcing the thunderstorm activity was now moving through the state, pushing the strongest activity north and eastward, giving the Prescott and Bellemont areas a much needed break, while putting Flagstaff and areas eastward under a greater threat.

Water Vapor Loop from 10:15-11:30 AM MST Wednesday October 6, 2010

water vapor beginning around 10Z

NWS Flagstaff Radar Loop 9:00 AM -1:00 PM MST (16:00-20:00Z) Wednesday October 6, 2010

Radar from 9am-1pm

By 3 PM MST, the lead shortwave was now moving across the northern part of the state, pushing the strongest activity northeastwards towards Southern Utah and the four corners, with scattered activity remaining across Northern Arizona. As the shortwave passed, the strong vertical forcing causing the thunderstorm activity diminished, and the winds shifted to more southwesterly direction, lessening the wind shear across the region. This marked the end of the severe weather threat for the region, as the best combination of instability and wind shear had now been displaced further north into Utah.

Water Vapor Loop from 1:30-3:00 PM MST Wednesday October 6, 2010

water vapor beginning around 10Z

In summary, it was the combination of extremely strong vertical wind shear, instability, and the vertical forcing of the lead shortwave that produced this severe weather outbreak. Due to the strength of the wind shear and the associated rapid motion of storm cells, many of the tornadoes had long, extensive path lengths. Given the magnitude and intensity of this outbreak, it is certain this event will go down in history as one of the most significant tornado outbreaks to strike the state of Arizona since record keeping began.

Click the following link to see a radar loop from 1 AM MST - 2 PM MST, Wednesday, Oct 6, 2010:

The following is a preliminary summary of the confirmed tornado events, and will be updated as additional information becomes available. All times are approximate and MST. Damage ratings are based on the Enhanced Fujita Scale.
  1. Blue Ridge Tornado (1:58 - 2:12 AM). EF-1 damage. Forest Service and National Weather Service employees verified 10-15 mile path with numerous trees down and several forest roads blocked. Damage intensity varied considerably along path, which varied from 75 to 400 yards wide.
  2. Bellemont Tornado #1 (5:07 - 5:35 AM): Considerable structural damage in and around the community of Bellemont. Aerial and ground surveys verified a semi-continuous tornado path from at least 9 miles south of Bellemont, extending northward crossing Hwy 180 northwest of Flagstaff. Total discontinuous path length of at least 25 miles. Preliminary estimates of damage intensity put this tornado at EF-1, with isolated EF-2 along forest track and in the Bellemont community. Additional damage stats include:
    -6 minor injuries.
    -Over 100 homes damaged in Bellemont, 21 homes sustaining significant damage (deemed uninhabitable).
    -At least one business (RV Sales) with damage with 30+ RV units demolished and tossed onto Interstate 40. Interstate closed for several hours.
    -At least one overturned truck on the Interstate.
    -Numerous forest roads blocked, campers stranded by fallen trees.
    -Track was approx 2/3 mile east of the NWS Bellemont Weather Forecast office.
  3. Bellemont Tornado #2 (5:58 - 6:40 AM): This tornado caused extensive forest damage (primarily south of Bellemont), along a discontinuous track which extended from 15 miles south of Bellemont, eventually crossing Hwy 180 northwest of Flagstaff. A significant and discontinuous tornado track was surveyed 15 miles to the north of Bellemont, and at least 15 miles to the south, resulting in a total path length of at least 30 miles. Very wide, severe forest damage (EF-2) occurred in the forest south of Bellemont. Additional damage stats include:
    -28 rail cars derailed in Bellemont.
    -Power poles snapped on Camp Navajo.
    -Numerous forest roads blocked, campers stranded by fallen trees.
    -Tornado visually sighted by NWS staff at the Bellemont Weather Forecast Office.
    -Track was 1/3 mile west of the NWS Bellemont Weather Forecast office.
  4. Garjon Tank Tornado (7:02 AM MST): This tornado caused extensive forest damage south of Bellemont. Based on severity of forest damage, this tornado is rated an EF-2.
  5. An additional tornado damage track was discovered northwest of Kendrick Park, crossing Highway 180, and west of the two Bellemont tornado paths that crossed Highway 180 in the same general area. Estimated at EF-1. Time of occurrence estimated at 7:38 AM MST.
  6. 11 miles southwest of Cordes Junction (10:30 AM MST): 50-yard wide tornado confirmed on the ground in grassland east of Interstate 17. Dissipated shortly afterward.
  7. 19 miles southeast of Tuba City (11:15 AM MST): Torndao collapsed three 500 KV electrical transmission towers. The towers were of metal truss construction. one tower was completely flattened. Photographic evidence and first-hand reports were provided by Arizona Public Service. Tornado damage intensity is rated at EF-3. (click for picture)
  8. Munds Park / Cosnino (12:05 - 12:20 PM): This tornado was visually sighted crossing Interstate 17 moving northbound...later observed 4 miles south of the Country Club neighborhood on the east side of Flagstaff. Little damage reported at this time.

Two additional short-path softwood tree damage tracks were located approximately 4 miles southwest of Rogers Lake, or 1 mile west of Mill Park, crossing forest road 526D. These two paths were separated by approximately 1 mile. Additional details on these two damage tracks will be presented after the survey process is completed.

The following is a preliminary summary of the hails events, and will be updated as additional information becomes available.

Approx 12 miles south-southwest of Bellemont 2.75 inch diameter
Cornville 2.00 inch diameter
Parks 1.75 inch diameter
Teec Nos Pos 1.75 inch diameter
Rimrock 1.25 inch diameter
Kachina Village 1.00 inch diameter
Cottonwood 1 mi south 1.00 inch diameter
Munds Park 5 mi north 1.00 inch diameter
Munds Park 1.00 inch diameter

The following is a map of the tornado tracks and damage pictures. Zoom in and click on the marker symbols to view the damage pictures. You can see a full-size picture by clicking on any of the thumbnails. Additional pictures and videos will be added as they become available.

Questions about this event or summary can be e-mailed to:

Update history: