In today’s summary, we look at an outbreak of 11 tornadoes that hit parts of Arizona on October 6, 2010. This was the largest number of tornadoes to strike the state in a single day since records began in 1950. This was also the largest single-day tornado outbreak west of the Continental Divide. Per the NCDC, Arizona on average receives four tornadoes annually. This is made more interesting by the fact that the original survey found only eight tornadoes. The SPC database still has eight tornadoes listed. As we started to update this summary, we noticed these discrepancies in the number of tornadoes. We reached out to Tony Merriman, Warning Coordination Meteorologist (WCM) at NWS Flagstaff, about this.
Tony emailed us back, saying: “Earlier this summer, we updated the StormData entry after locating and compiling all the storm survey findings from almost 10 years ago.” The information provided below is the most up to date and accurate information on this historical tornado outbreak.
From the NWS Flagstaff overview of the event, a strong area of low pressure over California pushed in tremendous moisture over Arizona on this day. A combination of extremely strong vertical wind shear, instability, and lift from the low-pressure system helped to set the stage for supercells. Three of the tornadoes passed within two miles of the NWS Flagstaff forecast office.
Here is a breakdown of the tornado ratings:
3 – EF0
2 – EF1
4 – EF2
2 – EF3
0 Comments