110 A High-Elevation Tornado over Northern Arizona

Wednesday, 7 November 2012
Symphony III and Foyer (Loews Vanderbilt Hotel)
David O. Blanchard, NOAA/NWS, Flagstaff, AZ
Manuscript (1.3 MB)

Mountain tornadoes, although uncommon, have been documented over the years across the western states. Recently, a tornado occurred over the San Francisco Peaks of northern Arizona. This group of volcanic peaks includes Humphreys PeakĀ—the highest point in Arizona at 12,633 feet.

The tornado formed over the gently sloping terrain west of the San Francisco Peaks and then moved up the west flank of Humphreys Peak. Damage was isolated along the early portion of the path at around 9000 feet. As it moved up the mountain, damage increased in both intensity and coverage with the peak damage occurring near 9800 feet. Higher up the mountain isolated damage continued until the tornado dissipated near 10500 feet. This makes this the third highest documented tornado in the United States.

The tornado occurred approximately 11 miles and within 90 minutes of the regularly scheduled rawinsonde launch from the National Weather Service Forecast Office in Bellemont, Arizona. This is the fourth high-elevation tornado proximity sounding taken from the Flagstaff NWS office in the past decade.

This paper will document and compare the environment of this event with other recent tornadic events over northern Arizona.

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