October 26-27 severe weather recap

Remember the crazy storms late last week? Weather Dan has taken the liberty of going through the data, assessing the damage, and basically letting us know what the mess happened.

November 2, 2010; 6:00 AM • by Weather Dan

As a forecaster, I always feel good when a forecast verifies. However, when that forecast includes tornadoes, it’s not always such a good thing for anyone and everyone within the storm’s path.

The cold front associated with the intense low pressure system I talked about on Wednesday brought severe weather to a pretty large swatch of the eastern and central parts of the United States.

As this cold front passed through Virginia late on Monday, October 25th through Wednesday, October 27th, it spawned numerous thunderstorms across a majority of the state, many of them severe.

In addition to the much publicized tornado on the northeast side of Richmond, the Virignia-North Carolina border was the focal point for many of these severe storms. Before I get into the meat of this, let’s talk about the Enhanced Fujita Scale, or EF scale, that is used to classify tornadoes.

It’s very rare that scientists are able to get an accurate measurement of wind speeds inside a tornado. Based on years of past research, meteorologists and wind engineers have come up with a rubric of damage indicators (including different types of trees and varying structure types); by assigning a degree of damage from 1 through 8 to the damage observed, those on a storm survey can estimate the highest wind speeds within the tornado.

Here is the complete EF scale:
EF0: Wind speeds 65 to 85 MPH
EF1: Wind speeds 86 to 110 MPH
EF2: Wind speeds 111 to 135 MPH
EF3: Wind speeds 136 to 165 MPH
EF4: Wind speeds 166 to 200 MPH
EF5: Wind speeds greater than 200 MPH

Let’s take a look at the tornadoes and other severe weather that occurred in Virginia and bordering counties as a result. These are listed in chronological order. The information listed below is as reported from the National Weather Service, and may be subject to change. Also, because this is taken directly from the National Weather Service statements, it’s in uppercase. Sorry.

October 26, 11:14pm EDT

King, Stokes County, NC
Event: Tornado
Maximum EF-Scale Rating: EF1
Estimated Maximum Wind Speed: 100 MPH
Maximum Path Width: 200 yards
Path Length: 2.25 miles

NWS Summary: THE TORNADO TOUCHED DOWN ON MOUNTAIN VIEW CHURCH ROAD AS AN EF0. IT THEN TRACKED NORTHEAST INCREASING IN STRENGTH AND REACHING ITS MAXIMUM STRENGTH AND WIDTH AT FLAT SHOALS ROAD. THE TORNADO CONTINUED TO MOVE NORTHEAST AND DISSIPATED AS IT PASSED SIZEMORE ROAD. THE TORNADO PRODUCED A WIDE SWATH OF TREE DAMAGE…WITH THE TOPS OF MANY PINE TREES SNAPPED OFF. THERE WAS SOME MINOR STRUCTURAL DAMAGE AS WELL…WITH THE ROOFS OF A FEW BARNS BLOWN OFF AND THROWN A COUPLE HUNDRED FEET. A CAR PORT ALSO COLLAPSED CRUSHING A CAR.

Fox 8, which covers the Greensboro, Winston-Salem and High Point areas of North Carolina, filed the following report about this and the second tornado that blew through the same community Wednesday night, which I’ll cover shortly.

October 27, 12:14am EDT

Aiken Summit, Henry County, Virginia
Event: Tornado
Maximum EF-Scale Rating: EF0
Estimated Maximum Wind Speed: 85 MPH
Maximum Path Width: 200 yards
Path Length: 5.4 miles

NWS Summary: THE TORNADO TOUCHED DOWN ON IRISBURG ROAD AND WAS INTERMITTENTLY ON THE GROUND FOR OVER 5 MILES AS IT TRAVELED NORTHEAST BEFORE FINALLY LIFTING ON PEACH ORCHARD ROAD IN PITTSYLVANIA COUNTY. SEVERAL TREES WERE DAMAGED OR SNAPPED AND THERE WERE FIVE OUTBUILDINGS DAMAGED. THREE HOMES ALSO RECEIVED MINOR DAMAGE. THE DAMAGE WIDTH OF ABOUT 100 YARDS WIDE WHERE THE TORNADO TOUCHED DOWN…AND GREW TO ABOUT 200 YARDS WIDE WHEN IT LIFTED.

October 27, 2:52am EDT

Virgilina, Halifax County, Virginia
Maximum EF-Scale Rating: EF2
Estimated Maximum Wind Speed: 120 MPH
Maximum Path Width: 100 TO 200 yards
Path Length: 4 miles

NWS Summary: TORNADO INITIALLY TOUCHED DOWN NEAR HIGHWAY 96 IN THE MAYO COMMUNITY AND CONTINUED INTERMITTENTLY ON THE GROUND MOVING NORTHEAST FOR APPROXIMATELY A MILE…DESTROYING ONE BARN…BLOWING SEVERAL ROOFS OFF SHEDS…MOVING ONE HOUSE OFF ITS FOUNDATION…AND DOWNING HUNDREDS OF TREES. THERE WAS SPORADIC EF0 TO EF1 DAMAGE IN THIS MILE OF THE TRACK. THE TORNADO STRENGTHENED…WITH EF2 DAMAGE…ALONG A CONTINUOUS PATH OF 2 MILES FROM WATTS TRAIL THROUGH NORTH FORK CHURCH ROAD…TO SHORTLY BEFORE LOWERY ROAD. APPROXIMATELY FIFTEEN TELEPHONE POLE WERE SNAPPED OFF. THOUSANDS OF TREES WERE DOWNED. THREE HOMES WERE DAMAGED…WITH WINDOWS BLOWN OUT…ROOFS DAMAGED…OR TREES FALLING ON THEM. NUMEROUS BARNS AND OUTBUILDING WERE DESTROYED. THE TORNADO THEN CONTINUED NORTHEAST WEAKENING TO SPORADIC EF0 OR EF1 DAMAGE TO LOWERY ROAD…BEFORE LIFTING AT LOWERY ROAD AT 302 AM EDT. NEAR LOWERY ROAD…ONE RESIDENCE WAS DAMAGED…WITH WINDOWS BLOWN OUT…ROOF DAMAGE…2 BARNS AND 3 OUTBUILDINGS DESTROYED…AND SEVERAL LARGE TREES DOWNED.

This was the strongest of the tornadoes to touch down in/nearby Virginia. WSLS-TV in Roanoke has the following report from the storm’s damage path.

October 27, 3:14am

5 miles north of Skipwith, Mecklenburg County, Virginia
Event: Tornado
Maximum EF-Scale Rating: EF0
Estimated Maximum Wind Speed: 80 MPH
Maximum Path Width: 100 yards
Path Length: 1.25 miles

NWS Summary: NWS STORM SURVEY HAS CONFIRMED A TORNADO NEAR THE INTERSECTION OF SKIPWOOD RD AND NEW HOPE RD. PATH LENGTH WAS APPROXIMATELY 1 1/4 MILES IN LENGTH WITH A PATH WIDTH OF APPROXIMATELY 100 YARDS. STORM DAMAGE IN THE AREA WAS CONSISENT WITH A HIGH-END EF-0 TORNADO…WITH WINDS ESTIMATED AT 70 TO 80 MPH. NUMEROUS TREES AND POWERLINES WERE KNOCKED DOWN…MINOR SHED DAMAGE WAS INCURRED AND SEVERAL TREE TOPS WERE TWISTED.

See the National Weather Service event summary page, including track map for this tornado.

Richmond’s WTVR CBS6 has a report on the damage.

October 27, 4:30am EDT

Providence, Caswell County, North Carolina
Event: Microburst
Estimated Maximum Wind Speed: 60 to 80 MPH
Maximum Path Width: 200 yards
Path Length: 0.50 miles

NWS Summary:THE NATIONAL WEATHER SERVICE IN BLACKSBURG VA HAS CONFIRMED THAT A MICROBURST…STRONG THUNDERSTORM DOWNBURST OF WIND…OCCURRED JUST EAST OF PROVIDENCE NORTH CAROLINA DURING THE EARLY MORNING HOURS ON OCTOBER 27 2010. THE SWATH OF DAMAGE WAS ABOUT 200 YARDS IN WIDTH AND LENGTH.

MICROBURST WINDS OF 60 TO 80 MPH WERE OBSERVED ALONG COMPTON AND BERTHA WILSON ROADS…WHERE NUMEROUS LARGE TREES AND TREE LIMBS WERE FELD WITH EXTENSIVE DAMAGE TO SEVERAL OUTBUILDINGS. 2 RESIDENCES SUSTAINED MINOR ROOF DAMAGE.

Caswell County seemed to be ground zero for microbursts during this event. A second event (described below) occurred about twelve hours after this event. Unlike tornadoes, microburst events are caused by a large downdraft from the base of a thunderstorm. Damage in microbursts is caused by straight-line winds, rather than the rotating winds of a tornado. It’s one of the reasons that the NWS performs storm surveys after an event like this; even though trees are knocked over and personal property is damaged, the cause is not always from a tornado.

October 27, 3:45pm EDT

Jericho, Caswell County, North Carolina
Event: Microburst
Estimated Maximum Wind Speed: 60 to 80 MPH
Maximum Path Width: 200 yards
Path Length: 2.00 miles

NWS Summary: THE NATIONAL WEATHER SERVICE IN BLACKSBURG VA HAS CONFIRMED THAT A MICROBURST…STRONG THUNDERSTORM DOWNBURST OF WIND…OCCURRED 2 MILES NORTH NORTHEAST OF JERICHO NORTH CAROLINA DURING THE MID AFTERNOON OF OCTOBER 27 2010. THE SWATH OF DAMAGE WAS ABOUT 200 YARDS IN WIDTH AND IN A DISCONTINUOUS AREA FOR ABOUT 2 MILES IN LENGTH.

MICROBURST WINDS OF 60 TO 80 MPH WERE OBSERVED ALONG OAKVIEW LOOP AND FITCH ROADS…WHERE NUMEROUS SHEDS…OUTBUILDINGS…AND BARNS WERE DAMAGED. NUMEROUS LARGE TREES AND TREE LIMBS WERE ALSO DOWNED…WHOLE TREES UPROOTED.

October 27, 5:00pm

Richmond, Richmond City, Virginia
Mechanicsville, Hanover County, Virginia
Event: Tornado
Maximum EF-Scale Rating: EF-1
Estimated Maximum Wind Speed: 80 to 90 MPH
Maximum Path Width: 200 to 250 yards
Path Length: 11.5 miles
Injuries: 1

See the National Weather Service event summary page, including track map for this tornado.

I left the gym and turned my phone back on about 20 minutes after the first tornado warning was issued for Powhatan, Amelia, Chesterfield, and the City of Richmond. By the time I got up to speed on what was happening (and wishing I had a better radar app on my phone), the second tornado warning, for Richmond, Henrico, and Hanover, was also issued. There was one non-life-threatening injury associated with this storm; my former manager at my day job when I worked and lived in Richmond was injured by a tree limb that fell on her while she was seeking cover. I’ve spoken with her via text message since, and she confirmed to me that everything and everyone is ok. Nothing broke, but she did get some wonderful painkillers. This wasn’t the strongest tornado in this outbreak, but it was the longest in terms of path length and duration, and it did plenty of damage.

There are lots of damage photos, but my favorite coverage is this video, where WTVR-TV’s chief meteorologist Zach Daniel analyzes some viewer-submitted footage. It’s by far the best imagery I’ve seen of the tornado so far.

NBC12 meteorologist Andrew Freiden also took the time to explain more about what the National Weather Service looks at when they do a storm survey.

October 27, 1010 7:05pm EDT

King, Stokes County, NC
Event: Tornado
Maximum EF-Scale Rating: EF1
Estimated Maximum Wind Speed: 90 to 100 MPH
Maximum Path Width: 150 to 200 yards
Path Length: 0.75 miles

NWS Summary: THE TORNADO TOUCHED DOWN NEAR KENNSINGTON AVE THEN TRACKED NORTHEAST TO SPAINHOUR RD…WITH INTERMITTENT TOUCHDOWNS IN BETWEEN. 25 HOMES WERE DAMAGED. MOST OF THE DAMAGE WAS IN THE FORREST OAKS COMMUNITY…WITH SEVERAL LARGE OAK TREES UPROOTED…6 ROOFS WERE PARTIALLY TORN OFF…AND A FEW GARAGE DOORS BLOWN IN. AT THE END OF THE PATH WHERE THE TORNADO LIFTED FOR THE LAST TIME CLOSE TO SPAINHOUR ROAD…A LARGE WOODEN SHED WAS FLIPPED OVER ONTO ITS ROOF…AND SEVERAL 1 FOOT DIAMETER TREES WERE SNAPPED OFF AT THEIR BASE.

WXII-TV, also in Winston-Salem, has an additional report from King, including an interview with National Weather Service meteorologist Steve Keighton, and a slideshow of viewer-submitted damage photos.

The final breakdown: 2 microbursts, and 6 tornadoes, including one rated EF-2. Nationwide, I had last heard that this system was responsible for 58 tornadoes, with another 16 pending confirmation. The current record for a tornado outbreak in October is 64, from the October 17-19, 2007 outbreak.

There are some important points that I want to reinforce. The first is that severe thunderstorms and tornadoes can strike at any time of day and at any time of year. First, be sure to invest in a NOAA Weather Radio. Unlike other places, there is not an organized network of sirens in our area, which makes it doubly important to make sure you have your own alert source. There are any number of models with a varying number of features, but when you purchase one, make sure to purchase one with SAME technology. SAME, or Specific Area Message Encoding, is a technology that allows your radio to only sound an alert for events that are taking place within your county. There are a variety of manufacturers out there, while I recommend shopping around for one that suits you best. Thankfully, there was only one injury among the whole of these storms, and nobody perished. Especially considering that several of these tornadoes struck in the middle of the night, and in rural areas where mobile home ownership is higher, the death toll could have been much worse.

Secondly, straight-line winds are just as powerful as tornadic winds, and are just as capable of causing damage. While most of the events in this outbreak were tornadoes, only the strong Virgilina and long-track Richmond tornadoes were responsible for more than an equivalent amount of damage compared to the two Caswell County, North Carolina microbursts. Straight-line winds are not as glamorous as tornadoes, and aren’t always given the same amount of press, but they are just as dangerous and every thunderstorm should be taken seriously.

Third, it’s important to plan ahead. Make sure you have a severe weather plan in place BEFORE a thunderstorm or tornado occurs. The Virginia Department of Emergency Management has information on how to prepare a tornado plan both at home or at work and information on how to prepare for a disaster. If you run a business, VDEM has information on how to prepare for a disaster at work as well.

It sounds cheesy, but it’s important: get a kit, make a plan, and stay informed. Once you make a plan, practice it, and be ready if severe weather strikes.

Thanks to the National Weather Service offices in Blacksburg and Wakefield, Virginia, for providing the data about each of these events.

November 2, 2010 6:00 AM 1