Monday, July 02, 2012

Inside The Virginia Derecho

By now, many of you have heard the term "derecho" used to describe the intense meteorological event that wreaked havoc across much of Virginia and the metro DC area Late Friday night.

A derecho is a long-lived, fast moving line of intense thunderstorms with straight line winds in excess of 60 mph. The line is often bowed. It is a warm weather phenomenon--the storms get their intensity and propulsion when the colder air associated with the storms clashes with warmer air in front of the line.

Friday's derecho started near Chicago in the early afternoon and raced southeastward at about 60 mph, fueled by an intense mass of steamy hot air that set records throughout the mid-Atlantic that day.

To its credit, the intrepid weather bloggers at the Washington Post's Capital Weather Gang issued an alert late Friday afternoon (about 4:00 pm) that there was a 50 percent chance of "storms capable of producing damaging winds and/or hail" coming through between 10 pm and 2 am, after already pummeling parts of the midwest. I doubt if too many people took notice, as they were mostly just trying to survive the hottest June day ever recorded in DC.

As the night progressed, the wife and I were watching Wimbledon highlights on television, while I surfed the weather radar. The derecho was clearly headed our way, and looked powerful on the weather maps. The wife was a bit dubious about my explanation of a derecho and what this might cause.

Right around 11:00, with Roger Federer coming back in his Wimbledon match, the lights began to flicker and dim. The derecho was clearly evident just a few minutes away on radar. We stepped outside and it was deadly still, muggy and hot. But we could see some pretty intense lightning flashes to the west.

Just minutes later, out of nowhere, an intense wind gust caused our front door to pop open. Then all hell broke loose in an instant. It was if we had been in the calm of the eye of a hurricane one moment, then experienced the back side of the hurricane coming through the next. The wind was howling, loose items were careening down the street, trees were swaying and tree branches snapping. Torrential rain (we got .60 of an inch in 20 minutes) was blowing in sheets sideways, punctuated by bits of hail. The lightning was strobing in non-stop white flashes with blinding blue flashes every few seconds as transformer after transformer blew.

Right at the outset, the power went out, then flickered back on. Then it went for good--everything around us, including the brightly lit commercial district a block from our home, was dark, but for the brilliant white and blue flashes illuminating them. Unfortunately, our automatic, natural gas fed generator failed to kick in.

The storm was at least as intense as anything we saw during the height of Hurricane Isabel a few years ago, but it only lasted about 20 minutes, if that. We watched the intense trail of lightning tail off to the east as an eerie dark quiet settled over Arlington. After the remnant rain settled to a sprinkle, I checked on the generator--no luck, it was definitely kaput, the victim of maintenance neglect.

At least it had cooled off, so we had a fine night of sleep.

The next morning, reality set in. More than 60% of Arlington was without power. Our Verizon FIOS service was out. Cell phone coverage was spotty, wi-fi down. We couldn't get any cash--ATM's either lacked power or were temporarily disabled due to network problems. We found an open diner for an early breakfast, but they couldn't process credit cards. By the time we left the diner (after charging a couple phones) there was a huge line out front.

We decided to get a hotel room nearby. We were just in time, as a line was forming there too. Since their systems were down, it was cash only also. Fortunately, we had the cash!

So now it's Monday, a full three days later. Our power has partially returned at home, but only some circuits are working. Apparently we're on a dual circuit with the power company, only one of which is working. Unfortunately, that does not include any air conditioning, nor our washer, dryer, dishwasher, or basement freezer. And our internet and cable are still out as well, but we do have our hotel room!

We're luckier than many. Huge swaths of Arlington still lack power. I went to our local Target store today to get some items and it was operating on a generator, leaving the back parts of the store eerily dark. Many traffic lights are still out, and gasoline is scarce (glad the Prius had a nearly full tank-- should last awhile). Our house, especially the upper two floors, is sweltering. We figure it will be the end of the week before things get back to "normal".

Sit could have been worse. If the storm had hit late afternoon, it would have caught a lot of people outside, or trapped on roads in their vehicles. Thousands of spectators at the AT&T Open in Bethesda would have been at risk. In that respect, we were lucky, although the storm still managed to take more than a dozen lives.

So that's it, for now, inside the derecho zone.