Posted by: Rob Viens | August 8, 2012

A Mighty Pampero

On August 8th Darwin experiences a strong wind, a “pampero” perhaps (more on this shortly).  His description is short, but it reminds me of weathering a rain storm in a tent – it is so close, yet you have a sense of security from that thin layer of fabric keeping you “snug” and safe from the rain.  Darwin writes:

 

“There has been a good deal of wind & rain.— In the evening the barometer fell, so the Captain determined immediately to strike Top-masts & let go another anchor. At sunset it blew a full gale of wind, but with our three anchors & no hamper aloft, we snugly rode whilst the breeze heavily whistled through the rigging.” (Aug 8)

 

The Beagle was well prepared for the winds that day, due to a captain who knew how to handle his ship well.  FitzRoy was interested in meteorology – in particular, he wanted ship captains to be able to predict the weather well enough so that they could be prepared for the worst.  He always looked for cause and effect when it came to the weather and planned accordingly. It was something that devoted a major part of his career to.

HMS Beagle in the Straits of Magellan (ca. 1900 by Robert Taylor Pritchett):
HMS Beagle

FitzRoy’s Narratives devote several pages to pamperos, though much of what he wrote was a description of a storm he experienced in Montevideo in 1829 on the first voyage of the Beagle. Let me try to touch on the highlights to give you a sense of FitzRoy’s passion for the subject.

First a definition of a pampero, in FitzRoy’s words:

“The land on each side of the Plata is so low, and those extraordinary plains called pampas, hundreds of miles in extent, are so perfectly free from a single obstacle which might offer any check to the storm, that a pampero sweeps over land and water with the weight of a rushing hurricane. Captain King has already described one, by which the Beagle suffered severely, in 1829;but having, to my sorrow, been more immediately concerned, I will endeavour to give a brief account of that disastrous affair, as a warning to others.” (Narratives, FitzRoy)

The rest of his story now jumps back three years to 1829 – note his attempt to carefully document all the precursors to the wind storm:

“On the 30th of January 1829, the Beagle was standing in from sea, towards the harbour of Maldonado. Before mid-day the breeze was fresh from N.N.W., but after noon it became moderate, and there was a gloominess, and a close sultry feeling, which seemed to presage thunder and rain. I should mention that during three preceding nights banks of clouds had been noticed near the south-west horizon, over which there was a frequent reflection of very distant lightning.

The barometer had been falling since the 25th, slowly, but steadily, and on the 30th, at noon, it was at 29.4, and the thermometer 78°. …

At about three o’clock the wind was light, and veering about from north-west to north-east. There was a heavy bank of clouds in the south-west and occasionally lightning was visible even in daylight. Myriads of insects, such as butterflies, dragon-flies, and moths, came off from the land; driven, as it appeared, by gusts of heated wind. At four the breeze freshened up from N.N.W., and obliged us to take in all light sails.” (Narratives, FitzRoy)

Then the storm begins:

“Gusts of hot wind came off the nearest land, at intervals of about a minute. The fore-topsail was just furled, and the men down from aloft, the main-topsail in the gaskets, but the men still on the yard, when a furious blast from the north-west struck the ship. The helm was put up, and she paid off fast; yet the wind changed still more quickly, and blew so heavily from south-west, that the foresail split to ribands, and the ship was thrown almost on her beam-ends, and no longer answered her helm. The main-topsail was instantly blown loose out of the men’s hands, whose lives were in imminent danger; the fore-topsail blew adrift out of the gaskets; the mainsail blew away out of the gear; the lee hammock-netting was under water; and the vessel apparently capsizing, when topmasts and jib-boom went, close to the caps, and she righted considerably. Both anchors were cut away (for the land was under our lee), and a cable veered upon each, which brought her head to wind, and upright.”

The storm was so severe that two sailors lost their lives, which FitzRoy blamed himself for, noting that he felt a “deep regret occasioned by the loss of two seamen, whose lives, it seemed, might have been spared to this day had I anchored and struck topmasts, instead of keeping under sail in hopes of entering Maldonado before the pampero began.”

The captain takes the time to describe their fate:

“When the main-topsail blew away from the men, who struggled hard to keep it fast, they could scarcely hold on, or get off the yard, and one young man fell from the lee yard-arm into the sea. Poor fellow, he swam well, but in vain: the ship was unmanageable, almost overset, the weather quarter boat stove, and the lee one under water: a grating was thrown to him, and the life-buoy let go, but he was seen no more. Another man was supposed to have been carried overboard with the main-topmast, as he was last seen on the cap.” (Narratives, FitzRoy)

The ship suffered significant damage, as well:

“The starboard quarter boat was stove by the force of the wind; and the other was washed away: and so loud was the sound of the tempest, that I did not hear the masts break, though standing, or rather holding, by the mizen rigging. Never before or since that time have I witnessed such strength, or, I may say, weight of wind: thunder, lightning, hail, and rain, came with it, but they were hardly noticed in the presence of so formidable an accompaniment.” (Narratives, FitzRoy)

However, even worse hot was the city of Montevideo and the smaller boats scattered throughout the harbor. FitzRoy goes on:

“In this pampero the masts of a vessel, at anchor off Monte Video, were carried away; and the upper cabin bulkhead of a Brazilian corvette was blown in while lying at anchor, head to wind, with her masts struck. But Maldonado seemed to feel its utmost violence; and there it certainly commenced like a whirlwind. A small boat, belonging to a poor man who carried fruit and vegetables to ships in the bay, was hauled ashore, just above high-water mark, and fastened, by a strong rope, to a large stone. After the storm it was found far from the beach, shattered to pieces, but still fast to the stone, which it had dragged along.” (Narratives, FitzRoy)

He continues with several more pages on other pamperos, but I’ll wrap up with his summary, which really gets at his attempt to synthesize all his observations in an attempt to try to come up with a way of predicting these dangerous storms:

“Before a pampero, the barometer continues to fall during several days, and invariably the water then rises. The gale commences, the barometer ceases falling and begins to rise, and very soon afterwards the level of the river is found to be sinking. For many following days the glass remains high, but the water continues to fall, and, generally speaking, the river is low while the mercury is steady and above the average height, which I should consider to be 29·9 inches.” (Narratives, FitzRoy)

So in that context, read Darwin’s description of the windstorm again, and note how comfortably the Beagle rode out the storm:

“At sunset it blew a full gale of wind, but with our three anchors & no hamper aloft, we snugly rode whilst the breeze heavily whistled through the rigging.” (Aug 8)

Although Darwin’s diary makes it seem like a minor event, this “comfort” was thanks entirely to the foresight of Captain FitzRoy – a darn good scientist himself. (RJV)

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Responses

  1. I’m having a growing appreciation for Captain FitzRoy. I found his descriptions above to be fascinating…

  2. […] phenomena which both to the South & North of it are comparatively rare.” (April 24) (See A Mighty Pampero and Watching a 19th Century “Plasma Screen” for more on these meteorological […]


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