Can you dive safely in bad weather?

Uh-oh. The weather stinks. The waves are big, the sky is gray. Or it's raining and the vis has turned to mud. But you paid to dive, you packed, you traveled, you're here and ready to go. What should you do now?

The Go/No-Go Decision Process
Yes, the boat captain is going out, but he'll be drinking cocoa in his wheelhouse while you're bouncing off rocks and filtering your breakfast through your second stage. Yes, your buddy wants to go, but he was always a chucklehead. You've got to make this decision for yourself. And if you do decide to go, you may want some special gear. Finally, you need to take extra caution in developing a safe, conservative dive profile for the specific conditions.

Condition #1: Angry Ocean

Stormy weather is the worst situation because it so often brings cold, wind, current and low vis. Your biggest problem, though, will probably be big waves.

Big waves mean a greater chance of seasickness on the way to the dive site. Gearing up while the boat rolls is more tiring and harder to do correctly. Falling on the wet, heaving deck is more likely. Waves mean strong surge in shallow and not-so-shallow water and the risk of abrasion against rocks. The greatest danger of all may be in approaching the heaving boat and climbing a ladder that is trying to throw you off. Then, as you stagger to your gear station tired and dazed, you have an opportunity to fall on the deck again.

The Go/No-Go Decision: Questions to Ask Yourself

How big is the boat? Bigger and wider boats will ride steadily in seas that would swamp outboard skiffs and even many "six-packs." Twin-hull styles are especially stable. Even when they roll and pitch, bigger boats have a slower, smoother motion that's less likely to make you sick or send you sprawling on the deck.

How hard will it be to reboard the boat? Setting foot onto the ladder and climbing it is the hardest, most dangerous single moment in rough-water diving. You need a large, well-designed dive platform at or just below water level with lots of sturdy handholds and a crew delegated to give you a hand. Some ladders, by contrast, are a challenge even in calm water.

Will you become seasick? Will your buddy? Some of us have iron stomachs, but most divers get at least a bit queasy in rough weather. Seasickness will leave you feeling surprisingly weak so that tasks that were just difficult (like climbing that ladder) become impossible.

Will the weather get worse? The critical time will be the end of your dive, when you are tired and need to reboard the boat. That may be a couple of hours from now. What's the forecast? Will the weather be getting better or worse? Predicting weather is a science about as exact as reading palms, but rising wind, increasing clouds and a dropping barometer are normally bad signs. On the other hand, if it's a clear day following yesterday's storm, the choppy seas are probably lingering effects and may well subside.

Will this be fun? If not, why are you even considering it?

Preparing to Dive

• Wear full-length coverage. Including hood and gloves. If you don't need it for conserving heat, you may need abrasion protection. Waves on the surface mean surge below. Water moves, rocks don't. Got the picture?

• Start gearing up early. It's especially important to be "put together" carefully when you expect rough conditions, yet gearing up will take longer when the boat is rolling.

• Double check. Straps and buckles will take extra strains. Make sure Velcro is clean and in good shape so it grips well. Make sure fin straps and mask straps aren't cracked and about to break. Don't forget to check your buddy's gear, and have him check yours.

• Surface signaling devices. While you're diving, the boat may drag its anchor or a mooring pendant may break, turning this into a live-boat dive. Or the storm may have generated stronger current than you expected, which sweeps you off course. Be prepared to surface some distance from the boat and signal it, both visually and audibly.

• Plan your dive. Now is the time to discuss explicitly with your buddy where you're going to go, when you're going to return, what air reserve you're going to maintain and all the rest of it. And review your hand signals.

• Reduce your "task loading." Diving itself will make greater demands today, so maybe you should leave the complex camera rig and the DPV behind.

Diving Smart in Rough Water

• Make transits under water. Forget about swimming on the surface to conserve air. Instead, figure out a compass course to the reef or whatever, descend to quiet water and transit below the surge. How deep depends on how big the waves are, but 15 to 20 feet should be plenty.

• Beware of rocks, caves, walls and wrecks. Surge often accelerates around corners and through openings. When it meets a wall it may become a strong updraft or downdraft. Wrecks, with their many sharp edges, abrupt angles and funnel-like openings, can be especially dangerous in high surge. Approach carefully and remember that surge, like the waves above that generate it, comes in sets. A period of mild surge may be followed by stronger surge a few minutes later.

• Make the safety stop deeper. If you feel enough wave action at 15 feet that it's difficult to maintain station, drop to 20 feet. Holding on to something stationary like the anchor chain helps when there is current and surge, but a boat that pitches heavily may jerk you up and down rapidly enough to cause an embolism risk.

• Approach the ladder carefully. Remember that waves and surge have sets of strong flows and weaker ones. Hang back until you get a sense of the rhythm, and wait for the weaker set. Approach on a rising wave or inflowing surge so that it carries you to the ladder. Hang on as it recedes, then climb quickly before the next flow. Don't start too close to the ladder. It's better to fall short and have to try again than to be thrown against the ladder.

Condition #2: Wind and Rain

Wind probably means at least choppy water, and it usually generates current, too. Rain probably means poor visibility, either because the sun is obscured or because runoff from shore brings silt into the ocean or both. But your biggest problem from wind and rain is the much higher risk of hypothermia during your surface interval.

Even the warm tradewinds of the tropics make an effective "swamp cooler" of a wet exposure suit. Though the air temperature may be over 80 degrees, it's not uncommon to see divers with their teeth chattering, desperate for the surface interval to be over so they can get back into the water and get warm again.

Add rain, which is usually cooler than the ocean, to constantly rewet your exposure suit and you've just accelerated the chilling.

Hypothermia is serious. It robs you of the energy you may need to meet a diving emergency. And it increases your risk of DCS because cold tissues have much less blood flow, so nitrogen is not being flushed out as rapidly.

The Go/No-Go Decision: Questions to Ask Yourself

Is this a passing shower? A gentle drizzle or a driving rainstorm?

How bad is the vis? How dark is the sky? How deep are you going? Is there much runoff? (Depends on the dive site.)

How much chop and current? Wind moves water, making waves and current. Waves and current build gradually as the wind continues. How long has it been blowing like this? If the wind has just started, expect waves and current to be worse by the end of your dive. Is the wind increasing? Frequently, wind builds in the afternoon and dies at nightfall.

Are you shivering? If you're that cold, you shouldn't dive. Shivering is nature's warning that hypothermia is getting serious.

Preparing To Dive

• Wear a thicker wetsuit. Wear more exposure protection than you might otherwise, so you come out of the water as warm as possible.

• Take surface signaling devices. The dive boat may drag its anchor or be obscured by the rain when you surface and look for it.

• Towel off and cover up during the surface interval. This is to prepare for your second dive by keeping you as warm as possible. A windproof/waterproof dive parka is an important piece of equipment in these conditions.

Diving Smart in Wind and Rain

• Reduce nitrogen loading. Dial back your dive plan for less depth and duration. End your dive with a couple of "clicks" more green on your computer than usual to make up for the fact that cold tissues don't offgas as rapidly as the tables and algorithms predict.

• Surface at the dive boat. Avoid making a surface swim back to the boat, since you may encounter choppy water and poor visibility.

• Reboard the boat carefully. If it's raining, ladders, handholds, decks and benches will be more slippery than usual.

Condition #3: The Vis Stinks

Waves and surge, strong currents, rain runoff, overcast skies and plankton blooms can all turn the visibility from gin and tonic to Bloody Mary. The risk here is buddy separation and disorientation. Uncontrolled ascents can occur when you lose your sense of rising and sinking. Some divers even experience vertigo when they lose their visual up-and-down references.

The Go/No-Go Decision: Questions to Ask Yourself

Have you done this before? Has your buddy? How comfortable do you feel diving in reduced visibility? Do you have trouble with claustrophobia?

Will the vis be better below the surface? Plankton and algae blooms in particular are often confined to the first few feet of water. Go below and the vis improves dramatically. It's hard to know until you try it, of course. A sensible plan might be: "We'll go down the anchor chain to 40 feet. If the vis doesn't get better, we bail."

What are your other stresses? If it's also cold, and there's lots of surge, and you're carrying lobster tools and a game bag for the first time, and you're not sure how much weight you need, and the BC inflator seems to be sticking a little ... maybe all that is just too much.

Preparing To Dive

• Take a dive light. It probably won't clear the fog much, but it will be useful at close range to peer into holes and paint colors. Short range is where things of interest will lie, because that's about all you'll see. A light will also make you more visible to your buddy, and vice versa.

• Take a compass. You'll be "instrument flying" for the most part.

• Take an ultrasonic locator. If you've invested in one of those magic "find the boat again" gizmos, now's the time to use it.

• Take a strobe. A strobe light attached to the anchor chain or ascent line can often be seen through the murk.

• Plan your dive. Decide on a fairly simple path through the dive site. Out-and-back patterns are easiest to follow. Note the compass course to and from the wall, reef or whatever is your goal. And review with your buddy what you will do if you become separated.

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