LITTLE ROCK, AR - The killer tornado that formed over Pulaski County on Sunday night before moving on into Faulkner County was at least an EF-3.*
That's according to the National Weather Service (NWS) office in Little Rock, which cautions that the rating is preliminary and could change when storm surveys are complete.
The NWS says Tornado #1 touched down in Paron, Mayflower and Vilonia.
Along the way, houses and businesses were heavily damaged or reduced to rubble. As of the evening of the 28th, there were 15 fatalities reported. If this number is correct, it would be the deadliest single tornado in Arkansas since the Interstate 30 twister (rated F4) that killed 15 people in Saline and Pulaski counties on March 1, 1997.
The NWS says the tornado started just inside the Pulaski County line, 4 miles north of Lake Norrell. There is an apparent continuous damage path for at least 29.2 miles, nearly to vilonia, where the survey will resume today.
Additional NWS details on the storm system:
Just after 700 pm CDT, a supercell (storm with rotating updrafts) rapidly intensified northwest of the Little Rock (Pulaski County) area.
A destructive tornado was produced, with the tornado tracking through Mayflower and Vilonia (both in Faulkner County) before apparently dissipating (according to radar) near El Paso (White County). The tornado has been given a preliminary rating of at least EF3 (136-165 mph winds).
Farther northeast, it appears the parent storm dropped one or several more tornadoes that headed toward Center Hill (White County), Denmark (White/Jackson County line) and Jacksonport (Jackson County).
All damage will be surveyed in the coming days by the National Weather Service to determine the tornado count and also the magnitude of the tornadoes.
What determined where the parent storm would ignite? Quite often, there is a boundary in play. In this case, clouds and thunderstorms earlier in the day kept areas to the north cool, with much warmer conditions and more humidity to the south. The dividing line between these air masses is where the parent storm focused.
Interestingly, the terrain can play an important role in determining where these boundaries set up. Cool air in the hills (the Ozark and Ouachita Mountains of the north/west) is hard to displace at times (it gets trapped), so the boundaries are frequently aligned along the eastern edge of the terrain, or close to the Interstate 30 and U.S. 67/167 corridors. This is considered "tornado alley" locally.
Before the tornadoes, a few storms unloaded very large hail in the northern half of the state. Tennis ball size hail hit Henderson (Baxter County), with ping pong to golf ball size hail at Dover (Pope County), near Waldron (Scott County) and south of Marshall (Searcy County). This happened between 400 pm and 700 pm CDT.
The other significant part of this story was the rain. There was a lot of it in northeast Arkansas. Locally more than five inches of water was measured in the twenty four hour period ending at 700 am CDT on 04/28/2014. This included a whopping 7.60 inches at Batesville Lock and Dam (Independence County) and Beedeville (Jackson County), 6.10 inches at Calamine (Sharp County), 6.03 inches at Corning (Clay County), 5.34 inches at Evening Shade (Sharp County), 5.30 inches at Ravenden Springs (Randolph County), 5.20 inches at Pocahontas (Randolph County) and 5.05 inches at Melbourne (Izard County).
This much rain caused extensive flash flooding, with numerous roads under water. There was a mudslide on Highway 25 southwest of Desha (Independence County). A bridge was submerged (likely by a creek) along Highway 25 between Batesville and Moorefield (Independence County). Highway 69 was flooded at Mount Pleasant (Izard County).
*On the Enhanced Fujita Scale, an EF-3 tornado has winds of 136 to 165 miles per hour.