Did we experience a "Derecho?"
What is a derecho you ask? A derecho is essential ‘a self-sustaining linearly-organized storm.’ A derecho often starts as a series of outflow boundaries/gust fronts extending from squalls/T-storms, advancing ahead of a pool of cold air aloft. Over time, these outflow boundaries/gust fronts can merge into a long line, and be self-sustaining.
To meet the definition of a derecho, the wind event must extend more than 240 miles (from end-to-end), including wind gusts of at least 50 knots, and have several, well-separated 65-knot gusts. Winds are ‘straight-line’ in nature (rather than circular like in a tornado or hurricane), and typically blow perpendicular to the motion of the derecho.
We never heard of one but on Shroud Cay we had the experience of one the night of April 26th and never want to experience one again. Around sunset the skies started getting darker and we could see a dark black line of clouds that extended into the distance with a clear line of light behind it. Both Kevin and I said, we think a storm is coming but just about the time we said it, within seconds the temperature dropped 15 degrees and the wind started picking up. Within 20 minutes, the wind was blowing hard but the scariest thing was the chop and waves had picked up. The water had gone from flat calm to a 4 foot chop in 20 minutes. It was dark now and our boat was rocking violently side to side and the winds were howling. We were anchored in about 6 feet of water and with the boat bobbing up and down so much, we were afraid we would hit bottom. There was one other boat in the anchorage and they were spinning around. I kept checking to make sure their anchor was holding. I huddled in the corner of our cockpit wide eyed and ready to start the engines if our anchor dragged. This went on for a couple of hours. Kevin had drifted off to sleep on the inside couch and I stayed up hoping it would pass quickly. The man can fall asleep during anything! The next day we heard that this “derecho” line started in Florida where in Lake Worth they had gusts of 70 mph. It then passed through the Berry Islands in the Bahamas where they had gusts of 60 knots and then on to the Exumas. Chris Parker, the weather guru who many cruisers subscribe to had notified cruisers of this event in an emergency email and on SSB radio. Needless to say, after that day we subscribed to his daily weather forecasts.
Lesson learned, after reading and hearing about cruisers experiences, we learned that many boats had dragged and it is best to already have the engines running during one of these events. Experienced cruisers said it was a “derecho” and they were rare. There has been only one other known derecho in the Bahamas in the last 13 years. Hopefully, we never experience another one.