Experiencing a Derecho

A Gentle Wind?

Wind is the breath of nature ferrying us gently across the water. Sounds wonderful, doesn't it? Wish it was always true. The reality is that wind isn’t always gentle. It can be a fierce, howling monster that spits piercing pricks of rain at you while savagely whipping your boat about, trying to tear your beleaguered anchor from the sand and cast you upon certain disaster. Despite all the modern advancements in forecasting, you don’t always know which wind you’ll be facing. As we learned…

Headed to Normans

After a short stop in Nassau, we headed to Normans Cay with our friends on Rollick on January 5th. The 36 mile sail was uneventful and we pulled into the anchorage at 4PM and relaxed. The weather was expected to be unsettled (coming from different compass directions) over the next few days, but it wasn’t supposed to be particularly strong. We had no idea just how unsettled it would be.

Normans Cay Inside Anchorage, Exumas, Bahamas

We went to sleep with cloudy skies and cool temperatures, a feature of the weather system we were embedded in. After a fitful night due to the strong current that flows through the anchorage, we left the anchorage in the morning to join a half-dozen boats anchored off the west side of Normans. Strong winds from the north-north-east were driving swells around the length of the island and into this wind-sheltered spot. We were hoping the wind would go east (as forecast) and give us respite, but it didn’t happen. We couldn’t bear the thought of another sleepless night with heavy rolling (the bane of a cruiser’s existence – even on a cat). So we pulled up the anchor and headed to a more sheltered spot on Shroud Cay a couple miles away.

Once we left the shelter of Normans, the winds began to buffet us and stir the waters into larger and larger waves. From an initial 15 knots, we first saw 20 then rapidly 25 and 30. Fortunately, we were headed away from the wind, so with a small scrap of jib showing, we headed south as the waves bounced us along.

As we reached the main channel between Normans and Shroud, the full force of the wind became evident. We started seeing gusts into the high 30s. The sea state became a jumble of short 4-5 foot waves that periodically rocked us violently side to side. This was a surprise. We hadn’t realized the weather had deteriorated so much.

We pulled into our new anchorage and carefully inched as close to the land as we could get before dropping the anchor. It was dramatically calmer than our previous anchorage and had better protection to the north.

Shroud moorings, west side, Exumas, Bahamas

We slept until, in the middle of the night, the wind started howling through the rigging. With the increased winds, the motion of the boat became more agitated. We heard our wind generator making sounds it had never made before. The boat was vibrating like a plucked string from the force of the wind. There were periods of intense thrumming as the wind picked up to 40 knots (46mph) briefly. We’d never experienced that before, yet it was a small taste of what was to come.

A Day to Remember: January 6^th

In the morning, we looked at each other and smiled at the calmer conditions that surrounded us. We’d easily survived the biggest winds we’d experienced sailing. The day looked promising.

We knew the weather forecast was calling for calmer winds, but from directions that required us to seek out better all-around shelter, so we headed back up to Normans anchorage (not the pond). The wild sea of the afternoon before was gone, instead we had a little chop that we easily sailed through in the easterly winds now present.

After picking out an anchoring spot and testing how well our anchor was holding, we looked forward to a warmer day and exploring the wreck of a DC3 airplane nearby. Then a squall came through. We are used to squalls, they happen periodically and generally involve a quick burst of wind, some rain and are gone in 15 minutes. This one blew to 25-30 knots and hung around for about a half hour. Longer than usual, but no big deal, and we were happy to have the boat washed and freshened.

Around noon, the sun peeked out of the clouds and friends from Isla Bonita visited us from their boat. They were in a much more secure anchorage, in Norman's Pond, over a mile away, but one difficult to get into or out of without the right tide and water conditions.

Shot at 1PM, 3 hours before the squall hit

Normans Cay anchorage, 3 hours before storm, Exumas, Bahamas

We hadn’t seen each other since last season and the kids played while we chatted. It all seemed innocent, except for the clouds on the horizon. Talk turned to whether they should leave to avoid the rain. Then the rain started and it looked like another squall was coming. Might as well wait for it to pass through.

We could see other cruisers hurrying back in their dinghies to their boats to escape getting wet. The wind was 20-25 knots from the north, nothing too surprising for a typical squall, but this wasn’t your average squall. Instead of dying away, the wind rapidly escalated along with the rain, until hazy sheets of rain, driven horizontally, were sweeping the anchorage.

Getting Nervous

When the wind hit 40, we knew this wasn’t your average squall. When it hit 50, we knew we were in trouble, because we could barely see the boats around us. Even though our anchorage had protection from the north and a quarter-mile fetch of shallow water, the waves at the boat quickly built to four feet or more, but they were coming so rapidly, one shoved on top of the other, that our boat didn’t “see” them. We were big enough to straddle them. Not so the sailboat next to us. It was pitching up and down like a crazed horse stung by a bee.

This video shows the anchorage while the winds were still in the 20-30 range

Beyond Nervous

As we looked at the chaos around us, someone noticed a sailboat sweeping from left to right in front of us while slowly approaching our bow. Time to turn on the engines. We would have to avoid them either dragging into us or possibly entangling their anchor with ours – and then both of us losing our hold to mother earth.

With a blast of wind that seemed more like a solid punch, our wind-meter jumped to 56 knots (64 mph). Our two wind generators were thrumming and screeching, working to tear themselves free of the boat. At least we were finally getting the darn things to produce some serious power. The boat shuddered as wind and waves tore at it. Sticking your face into the maelstrom wasn’t possible. It felt like getting sandblasted with little BBs.

Another shout over the radio! Someone pointed at a trawler that had dragged into the shallow area about a 100 yards behind us. We watched helplessly as the wind and waves bashed at it, their bimini in tatters. There was no way anyone could go help them, you’d likely flip your dinghy and need rescuing yourself. Then we heard panicked pleas for help on the VHF from a different boat a few miles north. A small 26 foot sailboat was adrift, with no engine and a woman begging anyone to come help them. We could all imagine her terror.

Still the storm raged on. After half an hour, there were still winds in the 50s. Ahead of us, the dragging boat had finally stabilized and was now about 60 feet from our bow, but coming no closer. But would the wind build again? At some point, a high enough wind will tear any boat loose from its anchor.

The rain stopped mid-way through the event and then it was just the wind ripping the spray off the waves and sending it blasting towards us. For over an hour, the wind was never less than 40 knots. In fact, when it got down to 30 knots, the weather seemed calm. I would never conceive 30 knots as calm, but it was. Wind energy follows the cube law, so the difference between 30 knots and 60 knots is not twice the strength, it is eight times as strong!

As the wind slowly moderated, we could see that the trawler had somehow miraculously gotten itself out of the shallows and was now holding station nearby using their motors. Their anchor chain dangled uselessly off their side. Everyone in the anchorage looked fine and there were no requests for help or rescue. As darkness descended and the wind still blew, we all lit up our boats to aid in seeing where everyone was. We didn’t know if there was another monster lurking in the dark.

Finally, the wind came down to 20, then 10-15 knots. We looked at each other wide-eyed at what we had experienced. We congratulated ourselves for surviving undamaged. We used the VHF to confirm that Isla Bonita had also come through unscathed.

We’ve Been Derechoed!

The next morning, we listened to Chris Parker (the cruisers' weather guru) on the SSB radio. He wasn’t sure what had broken loose on us (and many others along the Exuma chain). Winds had been reported as high as 106 knots at Cambridge Cay and there were damaged boats all the way south to George Town, about 55 miles away. The skies had not foretold of anything more than a typical squall, so most everyone had been taken by surprise at the severity. Boats in crowded anchorages began a panicked search for safety as neighbors dragged towards them, threatening serious damage. Thinking back, there really was no way, looking at the skies, you would have predicted the tremendous energy about to be unleashed.

Chris Parker thought the winds might have been caused by a “derecho.” A horizontal, straight-line wind (versus a cyclonic or circular wind) caused by a band of severe thunderstorms that form a long line and are created in certain conditions.

From Wikipedia:
A derecho (/dəˈreɪtʃoʊ/, from Spanish:derecho [deˈɾetʃo], "straight") is a widespread, long-lived, straight-line wind storm that is associated with a land-based, fast-moving group of severe thunderstorms. Derechos can cause hurricane force winds, tornadoes, heavy rains, and flash floods.

From Wikipedia, how derechos form

Chris predicted that this system would eventually move north-east towards Bermuda and would be a very rare example of a tropical low forming in January. Sure enough, NOAA began tracking “Disturbance 1” packing 50-60 mph winds the next day.

Chaos Documented

The following day, a gentle 15 knot wind blew out of the northwest. Time to leave Normans and head down to Staniel Cay. We nervously scanned the skies for threats, but it was a beautiful day and a wonderful sail south. Once we pulled into Staniel Cay, we got the word on how the storm had hit them.

Staniel Cay Yacht Club, Exumas, Bahamas

They experienced much the same thing, but it began at dusk instead of around 4pm. Winds were similar, in the 50-60 knot range. Friends of ours on Cool Cat, a Leopard 40 (just like ours), were anchored in an area with 360 protection – from normal weather. When the big winds hit, they started dragging and then their mooring bridle broke. The boat went sideways to the wind and dragged even more. As they tried to raise anchor, their windlass failed. As they tried to use their engines to steer, their port engine died. They noticed sparks as high voltage lines on the island were shorted by the 8-9 foot waves crashing onto the yacht club. Suddenly the island plunged into darkness and they lost their last visual cues. They were blind, knowingly drifting towards a shore with razor-sharp limestone rock. They hit the island on the bow, and as they were trying to steer away, their steering chain failed. Not the cable, the chain that goes from the autopilot to the helm. At that point, they were out of options. However, they were lucky (if you can use that term) in winding hard up against a dock that just happened to be next to them. It wasn’t a soft landing, metal bolts dug at the hull, but it was far better than grinding the boat to death on a rock.

Between Big Major and Little Major (islands just north of Staniel Cay), there were reports of 70- and 80-foot powerboats dragging through the crowded anchorage, causing panic, but apparently no harm. More unfortunate was the boat that went up on the famous “piggy beach” at Big Majors. They were lucky that someone was able to rescue them and, a couple days later, their boat was floated off.

These are just a few of the many stories of the terrifying derecho that scoured the Exumas on January 6^th, 2016. We will never look at another squall and not worry about what might be lurking within it. It's also time to take a close look at my bridle and figure out how to rig a temporary one in case I might need it some day...