Weather turned deadly for a few frightful moments on Friday night at EastLake Community Church near Moneta in Bedford County.
Strong winds emanating from a cluster of thunderstorms following along the U.S. 460 corridor from the Roanoke Valley toward Lynchburg collapsed a large tent during an outdoor service honoring the church’s 20th anniversary. One man was killed and 22 people were injured.
It’s a painful reminder that thunderstorm winds can become damaging and even deadly without being a tornado or a derecho, and that, given certain atmospheric conditions, severe weather can materialize quickly even amid a drought.
There will be at least some potential for severe thunderstorms in and near Cardinal News Southwest and Southside Virginia coverage area on Thursday, as a cold front and upper-level trough press into hot and humid air near our region.
It’s a setup fairly similar to what occurred on Friday, but of course, how it plays out for specific impacts at particular locations will be determined by variable details. Damaging winds, however, will again be considered the primary risk from any strong to severe storms that develop.
Gust front runs out ahead of storm
The culprit for Friday’s tragedy at EastLake was an outflow boundary, or gust front, running out many miles ahead of its parent storm.
Strong winds originating with thunderstorm downdrafts pushed outward from the storm.
Friday’s deadly wind event near Smith Mountain Lake was not an isolated episode, but rather, it was part of a large outbreak of severe weather. The majority of 280 severe wind reports nationally on Friday occurred in Virginia.
Thousands of utility customers lost power in our region on Friday with many reports of trees blown down.
Some locations also got an inch or two of rain in less than hour, inducing rapid runoff and minor flooding, while other spots not far away were left dry or got much lighter amounts as a long-term severe to extreme drought continues to plague the area.
It was not, however, part of a single, large organized cluster of storms pushing damaging winds continuously over hundreds of miles, not even remotely in the ballpark of what might be considered a “derecho,” a meteorological term invented in the late 1800s that has a lot more resonance since the deadly and destructive June 29, 2012 windstorm.
Rather, the storms formed into a series of clusters. There was also no indication of any rotation anywhere near the church tent collapse — it was very clearly by radar and observation a gust front with winds blowing one general direction, not a tornado.
There are sometimes eddies of swirling wind at the surface in outflow gusts called “gustnadoes,” but rarely are there tight circulations extending into the storm updrafts that would constitute a tornado.
Blazing heat contributed
Like 2012, the outbreak did emerge from very hot temperatures fueling instability that pushed cumulonimbus clouds high into the atmosphere.
Friday topped 100 degrees, hitting 101, at the John H. Kerr Dam in Mecklenburg County, while Roanoke tied a June 12 record high set exactly a century earlier in 1926 at 97.
These weren’t as extreme as the 100-105 temperatures that were common on June 29, 2012, but were 10-15 degrees above the norms for early June.
(On a much lighter note, one has to wonder if we’ve already had the summer’s hottest temperatures before the Cardinal Weather heat prediction contest’s June 20-Aug. 31 period even beings. Nevertheless, do remember to enter the contest, instructions linked here. The deadline is Friday night.)
Once these clouds began collapsing with condensation of moisture aloft, strong winds blasted downward from high aloft, spreading outward at the surface. The outflow boundaries sometimes triggered new storms and storm clusters, as cooler air interacted with warm, moist air yet to be disturbed by the clouds and prior storms.
Outflow boundaries and microbursts
Outflow winds are not the only way storms can produce damaging winds.
In some cases, damaging thunderstorm winds are deeply embedded within a storm’s heavy rain and lightning.
These microbursts can cause extremely localized damage within a storm that otherwise doesn’t appear to be severe.
One example of this struck Bogle Field in southwest Roanoke County on May 20, where a high school girls’ lacrosse game had been weather-delayed and the athletes and attendees moved into the nearby middle school.
This storm did not carry a severe thunderstorm warning and there was no indication from radar or prior observations that it would contain damaging winds, and likely it did not except in a very narrow radius of where the microburst blasted downward to the ground along U.S. 221/Brambleton Road in Cave Spring.
The wind blew with such force that it knocked down the scoreboard at the stadium that serves both Cave Spring and Hidden Valley high schools, literally bending the iron beams holding up the scoreboard.
Blessedly, the rain and thunder had already led to an evacuation of the stadium into indoor areas.
Reassessing how we react to storms
Because outflow winds can extend several miles beyond a thunderstorm’s core precipitation area, we should perhaps consider that potential as well as lightning within the general advice: “When thunder roars, go indoors.”
Severe thunderstorm warnings can get minimized or ignored by many people, partly because so many of them are issued and the actual severe storm effects — 58 mph winds or greater, 1-inch or larger hail — is often confined to very narrow corridors within an area that is warned. Most locations do not experience severe storm impacts in most severe thunderstorm warnings.
But these warnings are always issued by highly trained and professional public servants with strong evidence that there is or will likely soon be severe storm impacts somewhere within the storm’s path.
Perhaps, in light of recent events, we should remind ourselves that, at the bare minimum, we should always remove ourselves from vulnerable outdoor environments — swimming pools, bodies of water, golf courses, underneath trees, weak outdoor structures like tents, etc. — at the first rumble of thunder or any issuance of a severe thunderstorm warning, no matter how far away it may seem to our senses.
Weather-related tragedies are not a time for blame or self-righteousness, but rather, sympathy and empathy for those affected, plus reconsidering our own habits to improve our own safety and that of those we care about.
Journalist Kevin Myatt has been writing about weather for 20 years. His weekly column, appearing on Wednesdays, is sponsored by Oakey’s, a family-run, locally-owned funeral home with locations throughout the Roanoke Valley.
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