Tornado outbreak and floods of April 28 – May 1, 2017
Satellite image of storm system and associated supercells over the state of Texas at 23:30 UTC on April 29
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| Type |
Tornado outbreak Extratropical cyclone Flood Winter storm Blizzard |
|---|---|
| Formed | April 28, 2017 |
| Dissipated | May 2, 2017 |
| Lowest pressure | 991 mb (29.26 inHg) |
| Tornadoes confirmed | 70 confirmed |
| Max rating1 | EF4 tornado |
| Highest winds |
|
| Largest hail | 2.75 inches (7.0 cm) in Pocola, Oklahoma |
| Maximum snowfall or ice accretion | Snow – 39 in (99 cm) near San Isabel, Colorado Rainfall – 11.05 in (28.1 cm) near Houston, Missouri |
| Power outages | 61,200 |
| Casualties | 5 deaths (+15 non-tornadic), 70 injuries |
| Areas affected | High Plains, Western United States (Rocky Mountains), Ohio Valley, Upper Midwest, Southeastern United States |
|
1Most severe tornado damage; see Fujita scale Part of the 2016–17 North American winter and tornado outbreaks of 2017 |
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1Most severe tornado damage; see Fujita scale
The tornado outbreak and floods of April 28 – May 1, 2017 were a series of severe weather events that affected the central United States, producing life-threatening flooding and a major tornado outbreak. It formed out of a disturbance in the Southwestern United States on April 28, and caused significant impacts, including a heavy snowstorm in the Rockies, and other types of severe weather. Up to 3 feet (36 in) of snow fell on the cold side of the system, and up to a foot of rain fell in and around the central parts of the nation.
The most significant and damaging events of the storm unfolded late on April 29, when two large, long-tracked, and powerful wedge tornadoes struck areas near Canton, Texas, the strongest being an EF4. Together, the two tornadoes caused four deaths and many injuries.
On April 28, a stationary front was draped across the central United States, associated with cloudiness and showers. By 21:00 UTC, a surface low with a central pressure of 1,003 millibars (29.6 inHg) developed in central Kansas. Shortly afterwards, thunderstorms erupted along the stationary front, which required severe weather watches to be issued by the National Weather Service. A few tornadoes touched down, including an EF2 that caused considerable damage near Cameron, Oklahoma. By April 29, a ridge of high pressure centered over the Atlantic Ocean, this helped focus high levels of atmospheric moisture rising from the Gulf of Mexico along the front, causing immense clusters of heavy rain and thunderstorms to slowly progress eastwards – also known as thunderstorm training. At the same time, after deepening slightly to 992 millibars (29.3 inHg), the elongated area of low pressure was producing heavy snowfall in parts of Nebraska and Colorado, including Denver. Little change occurred over the next six hours as the front moved slightly eastwards; although a squall line was beginning to form, increasing the threat for large hail, damaging wind gusts and a few tornadoes. While the overall setup was not favorable for a widespread tornado outbreak, thunderstorms from earlier in the day left behind an outflow boundary draped across northeastern Texas, resulting in a localized area of enhanced low-level helicity. Deep moisture, high levels of CAPE, and low LCL heights were also present in this area as multiple thunderstorms rode the boundary and dramatically intensified into large tornadic supercells. A violent EF4 wedge tornado developed near Eustace, Texas and passed west of Canton, leveling homes, debarking numerous trees, and killing two people. Two more people were killed by a separate EF3 wedge tornado that passed east of Canton, destroying a car dealership along Interstate 20, tossing numerous vehicles, destroying homes, and causing significant damage further north in the town of Fruitvale. An EF2 tornado also touched down near Log Cabin and dissipated near Eustace, destroying additional homes and a communications tower. Multiple additional weak tornadoes occurred in Texas and in other states that afternoon and evening as well.
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Wikipedia