Anchorage 29.0 °F
Fairbanks 11.0 °F
Juneau 40.0 °F
Dreaming of a Derecho
I was at work one day looking at the radar and seeing something so unfamiliar to me. A line of red in the Mat-Su Valley moving quickly down the slopes of the Alaska Range, heading straight for Anchorage. I decided to go out of the office on Tudor and have a look.
From the parking lot you could see the towering cumulonimbus clouds topping out at over 42,000 feet. It was a warm day close to 80 but not quite, I could feel the warm breeze slowly picking up out of the northwest as the storm approached. I couldn’t believe what I saw. From what I could remember these were only supposed to happen in the Midwest.
In the distance you could hear the rumble of the thunder, and see the storm getting closer and closer. The winds continued to pick up as the wall of black and to my best judgment; it was now crossing the Cook Inlet.
I continued to just sit and stare in awe. From the building I heard someone yell. I turned around to see one of our reporters standing by the door.
“RYAN!!! GET INSIDE!” They said, but for some reason I couldn’t move, and nor did I want to.
“RYAN! RUN!!! IT’S A DERECHO!!” They yelled again. My mind clicked, I had to run. I had heard the term derecho in school and knew that this storm could kill me if I stayed outside.
I tried to run, I tried but my legs would barely move and by the winds had really picked up speed and the clouds were nearly on top of me. I looked across the street at the Subway and in an instant it vanished into black, engulfed by rain and hail. I grabbed at the door of my car.
No sooner did I get in the car than did the rain, hail and wind begin pelting the car. After about 10 seconds in the car the winds picked up. I guessed at more than 60 miles per hour. The car began rocking back and forth. Another few seconds and the winds continued to speed up. My heart began to race as I was wondering if my Nissan would stay on all four tires.
All of a sudden a strong burst of wind hit the car, coupled with the rain the car picked up on to its two right tires. Another gust and the car toppled onto its side. I was stuck in the driver seat trying to keep from being thrown to the passenger side.
I thought to myself, “What was I thinking? I knew a Derecho was dangerous. Why? Why did I come outside?” Then I thought, “Is this thing going to kill me?”
All of a sudden a beeping noise in the car, and I open my eyes and I realize my alarm is going off and it’s all a dream. I look at my phone and it reads 8:30am, August 14th 2013. That was the weirdest dream I have ever had… A Derecho, here in Alaska? Wow…
For some reason though, during the morning I couldn’t get it out of my head and finally decided I had to blog about it. So you’re probably thinking now after that story, what is a Derecho? How come I have never heard this term before and could this happen in Alaska? Let me start by saying, no, it will not happen here.
So what is a derecho? These are squall lines, or a strong line of thunderstorms that produce strong downbursts. These downbursts occur at the rear of the storm and can be extremely strong. In some cases these downbursts of wind are so strong planes have crashes miles before the runway they were supposed to land on. A derecho has to have a downburst of at least 57 miles per hour in order for it to be considered a derecho.
The term derecho is actually a Spanish word that means “straight ahead.” A very fitting word considering these storms generally don’t form tornadoes, but have very strong straight line winds.
Now a line of these storms can be fifty miles long or stretch as long as 500 miles, a scary sight indeed. Bow echoes also form when the rear inflow jet flowing into part of a squall line grows stronger than usual. When this bow in the storm forms it then produces multiple cells that can stretch out for miles long and produce these damaging winds.
The worst part of these storms is that they move quickly. In a 24 hour period a line of storms in 1977 moved over 800 miles and crossed 3 states and had winds up to 157 miles per hour! That is stronger than some hurricanes. Truly an incredible feat.
Now, why don’t we get them in Alaska? Simple, are weather is too influenced by the water and the terrain is too mountainous for us to get storms like that. We also don’t have the type of instability that much of the plains get. They get CAPE (Convective Available Potential Energy) values into the 3 and 4 thousands whereas we will be lucky to see instability in the 2 to 3 hundreds. It just doesn’t happen.
As for my dream, it’s all written down and now I can sleep again tonight.