Squall Tactics for Sailors

Posted by Darrell Nicholson at 05:27PM - Comments: (6)

Waterspouts often accompany squalls. This one passed us 15 miles out of the Dry Tortugas, it was moving to the left of the frame. The usual advice is to take bearings and sail or motor 90-degrees to the direction it is moving.

The danger in running before a squall (or jibing downwind, a tactic sometimes employed by Transpac racers) is the inevitable wind shift that can cause an accidental jibe. Since squalls are usually short lived, with the strongest winds lasting less than 20 minutes, simply reducing sail to a safe configuration and motoring or motorsailing through or past the squall can be a less taxing approach than trying sail through it. What is a "safe" configuration?

Gusts much over 40 knots are not common, but some devastating downbursts in excess of 50 knots can occur in volatile areas. (The fatal squall line that struck the fleet in the 2011 Chicago-Mac race is a good example). In some cases, dropping all sail and motoring through the highest gusts makes sense when a particularly nasty squall line threatens. 

While every squall is different, there are a few rules of thumb that can help guide your decision-making process. The following bits are culled from my own experience and a couple of weather books I’ve found helpful over the years, Bill Biewenga’s “Weather for Sailors,” and David Burch’s “Modern Marine Weather.” Burch’s book has some handy illustrations showing the direction of wind flow around a typical squall. I’d be interested in learning the titles of other books that cover squall tactics in detail—most seem preoccupied with hurricanes and winter gales, storms that the average sailor rarely encounters.

If you are the type who benefits from seminars, look for those offered by former NOAA forecaster Lee Chesneau (www.weatherbylee.com), author of “Heavy Weather Avoidance.” 

The strongest wind gusts will be at the leading edge of the squall line, with the highest increased winds often arriving before the rain.

Squall Tips

Keep in mind, there are plenty of exceptions to these rules of thumb—but as Burch puts it, you have to start somewhere.

  1. Taller clouds generally bring more wind.
  2. Flat tops or “boiling” tops can bring brisk wind speeds and sudden wind shifts.
  3. Slanted rain generally indicates there is wind. Squalls often move in the direction of (or sideways to) the slant, so don’t assume that the cloud is “dragging” the rain behind it, as it might appear.
  4. Track cloud/storm movement by taking bearings on the center of the storm (not the edges).
  5. Watch for whitecaps below the clouds, indicating strong gusts.
  6. “Tilted” clouds often bring wind.
  7. The first gust, usually a cool downburst, can strike one-to-two miles before the cloud is overhead, and before the rain starts, so reduce sail early.
  8. The strongest gusts and the increased wind accompanying the squall generally blow in the direction of the cloud movement, i.e. outward from the “front” of the cloud. However, increased wind blows outward from all sides of the cloud.
  9. Squalls do not necessarily come from the direction of the mean ambient wind, so squalls to weather are not the ones to worry about. It is the ones to the right of the true wind, about 30 degrees, that are headed toward you (i.e. if a southerly wind is blowing, it is the squalls to the southwest to watch for).
  10. The strongest wind comes with or just before the light first rain. If the squall arrives already raining hard, the worst winds are usually past, but strong gusty winds are still possible.
  11. Behind any squall is a unnerving calm.
  12. If you are faced with a number of successive squalls, they will often follow a predictable pattern, allowing you to fine-tune your tactics.
  13. If you plan to bathe in the downpour, go easy on the shampoo—you might not get enough rain for a rinse.

Comments (6)

Useful article on a subject that affects almost every sailor eventually. I have 20 years experience sailing on Lake Erie, where squalls are fairly common weather events. When I was sailing an Ensign, which is about 21', and I saw a squall coming I would make sure everyone had a lifejacket on, take down the jib, start the outboard engine, and take down the main.

When I was sailing my Catalina 30 with a standard rig, fin keel, and roller furling headsail I had more options. If I anticipated squalls early enough, we would use our high "Yankee" cut 90% jib on the furler and put two reefs in the main sail. If we anticipated gusts over 35 knots we would furl the jib a bit and totally furl the jib if the gusts were over 40 knots. Early in the process we closed all hatches and the companionway. In virtually all situations we left the main up with two reefs. Depending on the situation, we might start the engine.

We take take a similar approach today with my current boat, a Beneteau Oceanis 321 with a standard rig and a shoal draft keel. We put two reefs in the main if we see a squall coming. Depending on which headsail we are flying we will reduce the sail area to help keep healing to below 15 degrees. I prefer to keep the deeply reefed main up to help steady the boat and maintain steerage. The engine can help but I rarely sail through a squall on engine alone.

Posted by: mark2 | July 19, 2019 3:33 PM    Report this comment

During our ocean crossings at night we always sailed rigged to handle about 40 Knots of wind no matter the actual wind. That way we avoided a midnight panic in the face of a sudden squall. We were NOT racing and had the objective of arriving safely and undamaged. Mostly we did. What is rigged for forty knots? Know your boat.

Posted by: ARGONAUTA I | July 11, 2019 10:47 AM    Report this comment

Nice review.
I've found that #7 is variable. ("The first gust, usually a cool downburst, can strike one-to-two miles before the cloud is overhead, and before the rain starts, so reduce sail early.")
Several times in the past few years I've felt a brief warm wind before a squall, one of them with 50kt gusts, as measured at a local yacht club. Sailing in Maine may be a factor: warm breezes are rare.

Posted by: Surrymark | July 11, 2019 10:39 AM    Report this comment

The other danger in running downwind in a squall, particularly in smaller boats and many multihulls, is pitchpole and capsize; by the time you realize that you are overpowered dead downwind, there is no escape, the main won't come down, and the only hope is that bows are not driven under nor the stern lifted enough to lose steering. While a well-sealed cruising boat can survive a knockdown with minimal harm, a boat with open hatches or companion way is at great risk; with enough water swallowed, she won't come back up.

Every boat has its own set of rules regarding squall strategies. Having spent most of my life sailing performance multihulls of different sizes, my strategies are based upon their inherent strengths and weaknesses.
* Never get surprised.
* Since multihulls reef for the gusts, that means bare poles or very deep reefs in a squall, before it hits. Reefing during a squall is embarrassing.
* Down wind is nice under bare poles or the tiniest of sails; multihulls are easy downwind when not over pressed by sail.
* Forereaching is good (small jib in tight, traveler way down). Keeps her moving with her head up, but slowly. The full batten main won't flog.
* Never heave to; you will get sideways, which is bad. Keep moving.
* Never motor a very light cat straight into a squall (they can go over backwards). A slight angle is safer, with the helm over and going slowly forward.

Posted by: Drew Frye | August 21, 2014 8:42 PM    Report this comment

Well written, thanks. With rollerfurling main and Genny, I always go to bare poles and the iron Genny for squalls and have never been sorry that I did.

Posted by: Catalina 42 | August 20, 2014 1:26 PM    Report this comment

A good refresher if you haven't experienced a squall recently. On the other hand it's unlikely that we forget our first nasty squall encounter. I think it may be helpful to note the trailing sea that follows the squall line. Although it's not happened to me I can envision stripping poles under pressure while getting slapped broadside by a fast moving roller. Even under power I prefer to run ahead of the storm, for the short duration the loss of time or later arrival is well worth any safety measures taken.

Maybe I'm a bit crazy but these are the most exciting experiences I've enjoyed in my forty years of sailing. It's a heck-of-a rush and a test of your seamanship and decision making when these things occur and a great experience to share with your favorite crew.

Jim McAleer
Irish Wake II
Port Washington NY/Delray Beach FL

Posted by: James M | August 20, 2014 12:09 PM    Report this comment

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