Updated: 9 April 2012
The values in this report are preliminary, and the final counts and results will change as tornado events are investigated and confirmed. This month’s report will not be updated with final statistics. For final information please visit the following sites:
According to data from the Storm Prediction Center, the count of preliminary tornado reports during March — 223 — was over 270 percent of the average monthly count of 80. Depending on the confirmation rate, the March 2012 tornado count could surpass the previous most active March on record of 1976 when 182 tornadoes were confirmed. A large portion of the tornadoes occurred during a large severe weather outbreak on the 2nd and 3rd of the month, when there were 132 preliminary tornado reports. A significant warm weather event enveloped much of the eastern two-thirds of the contiguous United States during March, and the warm temperatures were accompanied by increased dewpoints and instability much farther north than is typically experienced during the month. This frequently created ideal severe weather conditions over a large area of the Lower-48.
An early-season tornado outbreak impacted the Ohio Valley and Southeast on March 2nd – 3rd. According to the SPC, over the two day period, there were 121 preliminary tornado reports on the 2nd and 11 on the third. It was early in the season for a tornado outbreak of this magnitude, and once the tornado reports are confirmed, it will likely be the largest March tornado outbreak in the 1950-present record. April through June is typically the most active period for tornado activity across the United States. This tornado outbreak was driven by a large low pressure system moving through the mid-Mississippi Valley into the Ohio Valley and the associated cold front. Warmer-than-average temperatures in the 70s and 80s (degrees F), combined with strong wind shear, created ideal conditions for the tornado outbreak. The strongest tornadoes were focused across Illinois, Indiana, and Kentucky, where an EF-4 tornado was confirmed in southern Indiana. In total, there were 40 tornado-related fatalities during the outbreak. Damages for the outbreak were expected to exceed 1.5 billion U.S. dollars.
On March 15th, an amplified weather pattern, more typical of summer, allowed warm and moist conditions to surge northward into Michigan. An upper-level low pressure system moving into the unstable environment set off several thunderstorms across the region. One of the tornadoes, near Dexter, Michigan, was rated an EF-3 with winds of 135-140 mph. The tornado marked the earliest EF-3 to impact the state in the 1950-present modern record. The tornado had a 7.2 mile path length, with a maximum width of 800 yards, destroying nearly 130 buildings in its path. There were no reported fatalities or injuries with the storm.
On March 9th, a cut-off low pressure system impacted the Hawaiian Islands, bringing heavy rainfall and severe thunderstorms to the windward portions of the archipelago. A waterspout (a tornado over water) made landfall on Oahu hitting the towns of Lanikai and Kailua. The tornado caused some minor damage and was rated an EF-0. Tornadoes are rare in Hawaii, with only seven confirmed tornadoes impacting the state since 1950. The same system produced a severe thunderstorm which dropped a hailstone on Oahu measuring 4.25 inches long, 2.25 inches tall, and 2 inches wide, breaking the record for largest hail stone measured in Hawaii. The previous state record hailstone was 1 inch in diameter.