By Tom Neale, 5/4/2006
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In the Bahamas they used to say, “when she blow one day she blow two. When she blow two days she blow t’ree. When she blow t’ree days she blow and she blow and she blow.” Sometimes the wind just sets in with a vengeance and it seems like it’ll never ever stop. I know you’ve seen this. It doesn’t just happen in the Bahamas. It’s happening right now as I write this, as we’re trying to make our way up the east coast.
For several days we’ve had steady strong northerly winds, making a gale out in the ocean and winds generally 20 to 25 sometimes 30 inshore. We’ve been in the ICW in North Carolina. Even here the winds have been strong enough to make many boats stay in marinas or snug anchorages. It was blowing so hard a few nights ago that when we wanted to go into a marina to see some friends we decided not to because we didn’t want to dock in winds that high. It was safer and much easier to put the hook down in a familiar anchorage. When this happens it can make boating anything from difficult to dangerous.
Long periods of high winds can even cause groundings for sail and power boats in the ICW in ways that many don’t expect. This long period of strong northerlies piled the water down into the lower end of the North Carolina sounds, having blown it out from the northern ends. I talked with a veteran tug captain as I followed him northbound into Currituck Sound and he said, “I’m seeing things I never saw before here.” Boats were getting stuck all over the place. And this was a day after the winds had tapered off. It took about two more days for the water to return to its normal levels, flowing with exceptionally strong currents from south to north.
Different weather factors can cause this, but often it’s caused by what we on Chez Nous call a “squeeze play.” It happens when a low pressure system is hanging out in one sector of the world and a high pressure system is hanging out in another. In this one, the strong low pressure was out over the Atlantic, toward Bermuda, creating great danger for anyone out there in other than large well found ships. The high pressure was over the northeastern part of the North American continent, even up into Canada. What did that have to do with Cape Hatteras and the coast of North Carolina?
The low was churning counter clockwise out over the ocean. The high was swirling clockwise over the land. As the two air flows came together they complemented each other in speed, building high winds—mostly northerly. But another factor was in play, caused by pressure gradients. If you look at a surface air pressure weather map you see lines running around areas of high and low pressure. The closer they are together, the more quickly the pressure changes as you move away from or toward the center of the system. Steep pressure gradients mean wind. If you see the lines close together, you can expect wind. I’ll never forget sitting at anchor behind a rock in the Exumas and getting a weather fax through my SSB and seeing the gradients for the so called “Storm of the Century” in March, 1993. It was truly awesome, with tight lines almost touching each other over most of the lower western Atlantic. Fearful. People died in that storm, including 4 that had been on a boat in our anchorage area. They took off across the Gulf Stream with the storm building. And this was just a very deep very huge low. There really wasn’t much of a squeeze play factor involved. We held on for dear life for several days waiting for it to blow out.
Squeeze plays can make a lot of wind even if the low isn’t all that bad a system by itself, nor is the high. When they settle in over the Bahamas you can hear people begin to go a little nutty on the VHF, because everyone gets so tired of being pinned to their boat out at anchor, often unable to even take a dinghy ride—or at least one in which they don’t get completely soaked. It’s a time when many people start swearing that they did indeed tie their dinghy well to the stern last night, that something must have “gone wrong” as they hail friends and neighbors downwind to try to find their rubber ducky scooting away on the wind toward liberation. Once in a long squeeze play blow, on St. Patty’s day, a cruiser read Irish stories on one of the little used VHF working channels to the entertainment of all the boats within range.
Squeeze plays also mean shipwrecks and sometimes death. Cuts and inlets become treacherous as huge seas break, stumbling first on the island shelf and then crashing over the rocks. When boats that have been caught out at sea try to come in to find relief behind the islands, they sometimes founder, sometimes are flipped, and sometimes are pushed out of control onto rocks. Small boats and dinghies have trouble too. Typically, the small dinghy and outboards are not up to the job, although the rig may have done well putting around a calm anchorage back in the summer time in the states. And people misjudge just what a strong prolonged wind can do. Once two people thought they’d row the short distance across a marina to another boat. They were blown out of the marina entrance and weren’t seen again—until they were spotted by a searching vessel two days later. Both were still alive, but neither had enjoyed the trip.
The odd thing is that this weather phenomenon sometimes surprises people. It shouldn’t. Unlike some other weather features, it’s relatively easy to predict at least several days before it develops. A low and a high forming in adjacent areas, even though broad, are hard to miss. There are various ways to find out. You can make your own prediction by downloading weather maps every day. With a satellite phone or SSB or ham radio, you can do this far out at sea. You can listen to the high seas weather, or VHF weather. Often we’ve found that the VHF forecasts don’t do an adequate job of describing what’s going on, but you can usually read between the lines. Many who go offshore subscribe to weather services which give much more thorough information.
Unfortunately we’ve found that the TV weather forecasts have become less and less meaningful to boaters. The pretty people on the tube tell you things that you can learn by looking out the window. As we travel up and down the coast we’ve found some very good forecasters who show weather maps and explain them, but these are becoming rarer. But it really helps to learn weather basics and have good weather data sources, so you won’t be squeezed out of a good day on the water.
Copyright 2004-2005 Tom Neale