Early-March 2023 North American storm complex

An intense low-pressure system produced widespread impacts across the United States in early March 2023. Additionally, an outbreak of 35 tornadoes affected 12 states from the Southern United States to the Great Lakes. In all, the storm system killed 13 people due to flooding and strong winds. At least 17 other people were injured.

Western United States
On March 1, the snowstorm in Arizona led to many pileups, and several roads such as I-40, I-17, and US 93 closed. In addition, I-80 closed from Applegate, California to the Nevada state line. In Nevada, portions of US 93, I-11 and I-15 were shut down as well, as well as several state highways. On March 1, the Northern Arizona University cancelled all in person classes. Joshua Tree National Park temporarily closed due to the inclement weather, and the San Bernardino National Forest shut down for two weeks. All park roads in Mojave National Preserve were shut down, and partial closures also occurred in Redwood National Park, Sequoia National Park, Kings Canyon National Park and Death Valley National Park. A supermarket in Crestline, California collapsed due to the snow. One person was killed due to the storm in California. Further east, I-40 westbound lanes was also shut down in Gallup, New Mexico. In the state of Idaho, portions of US 20 were shut down as well.

Southern United States
On March 1, hail fell in north Texas, some of which were up to half-dollar size. Hail fell in Dilley, Texas, causing damage to windows and cars, as well as a severe thunderstorm warning for softball sized hail in Pearsall, Texas. On March 2, severe storms led to a ground stop at Dallas Fort Worth International Airport. On March 3, the storm led to the lowest pressure on record in Louisville and Bowling Green, Kentucky. Mammoth Caves National Park was shut down on March 4 due to storm damage. Nearly 400,000 residents in Kentucky alone lost power, with over 1800 being placed under boil water advisories. The storm resulted in five people being killed in Kentucky, three in Alabama, two in Tennessee, one in Mississippi, and one in Arkansas.

Eastern United States
On March 3, snow led to many snow emergencies in the Albany, New York metropolitan area and near Pittsfield, Massachusetts. Ultimately, 7.8 in of snow fell in Albany. 72,700 customers in eastern New York lost power due to the winter storm. On the night of March 3, WestJet cancelled all flights out of Toronto Pearson Airport due to the snow. The snowstorm also shut down Detroit Metro Airport on the night of March 3, and a ground stop was imposed at Atlanta Hartsfield-Jackson International Airport due to severe weather. Over 100 flights were cancelled due to the storm at Boston Logan International Airport. The Maine Turnpike had a speed restriction as a result of the storm. Between March 3 and 4, up to 1.49 in of rain fell in Newark, New Jersey, with 1.14 in of rain falling in New York City.

March 1
While confidence for a widespread severe weather outbreak increased for March 2, an enhanced risk for severe weather, including the possibility for a few strong/EF2+ tornadoes, was issued for March 1. A large capping inversion, placed along northern Louisiana, was expected to contain the atmosphere from initiating convective activity, but the presence of moisture, daytime heating in the area, and steep mid-level lapse rates, made the environment favorable for severe weather, including the possibility for supercells capable of all hazards. Given the favorable parameters in place, the Storm Prediction Center (SPC) issued a large corridor, extending from extreme northeastern Texas, most of central Arkansas, northwestern Mississippi, and southwestern Tennessee, were the highest probabilities for tornadoes were located. A slight risk, lined with a 5% risk for tornadoes, was issued around the main area of concern, and extended into central Tennessee, and northern Alabama. A large, 30% risk for strong, damaging wind gusts was also placed along central and eastern portions of Arkansas, extending into northwest Mississippi and southwest Tennessee, as was a hatched corridor for very large hail was also introduced for this corridor.

March 2
As a large, widespread, and damaging storm complex event was occurring throughout the Great Plains, which unleashed powerful damaging winds and tornadoes across Texas, Oklahoma, and Kansas, the SPC highlighted a potential area for the risk of severe weather in the following days, with the main, 30% area for severe weather centered around eastern Texas, northern Louisiana, southern Arkansas, middle portions of Mississippi, and western Alabama, as conditions were expected to be very favorable for the development of thunderstorms capable of all severe weather hazards.

After introducing a massive level 3/enhanced risk for March 2 on February 28, which now included portions of southeastern Oklahoma, the SPC upped the threat to a level 4/moderate risk, throughout a corridor centered along the Ark-La-Tex region, clipping into extreme southeastern Oklahoma, on March 1. Throughout the risk area, the environmentally favorable conditions for severe weather were set in motion due to the presence of abundant moisture, instability that was expected ahead of a cold front starting from north-central Texas, and intense wind shear prevalent across the entire region. With this setup, a linear cluster of discrete supercell thunderstorms was expected to develop, and given the favorable wind and instability patterns, a 15%, hatched risk for strong/EF2+ tornadoes was placed along the moderate risk area, while a large, surrounding 10% hatched risk for strong tornadoes was placed and extended into central portions of Arkansas, and all the way into northwestern Mississippi. At the 1630 UTC update on March 2, however, the 15% hatched area was removed due to lingering uncertainty about the timing of the most favorable wind shear for tornadoes versus the convective mode of the ongoing storms. Despite this, a moderate risk remained due to a 45% hatched risk for damaging winds and 45% hatched area for large hail that had also been issued.