Atmospheric conditions leading to strange tide levels
Posted by Bob Marshall, The Times-Picayune December 15, 2008 3:21PM
One recent morning charter skipper Dudley Vandenborre was preparing for a fishing trip when he got a shock: Lake Pontchartrain was gone.
Well, not completely. But close enough to stun a man who has been fishing the lake for more than 50 years.
"I was lowering the boat (on the slings) at the dock, I really didn't think the boat would reach the water -- that's how low the tide was," Vandenborre recalled. "I had two or three turns of the pipe left before it finally began to float. We've been on this canal for 20 years, and that has never happened before. Ever.
"No one has ever seen the water this low. That's what everyone is talking about."
For three weeks extremely low tides have been the talk -- and complaint -- among anglers across the southeastern marsh. And these aren't your average weekend whiners, but men who make their living on the water. From Venice to Leeville, Lafitte to Delacroix, veteran marshmen are calling this the lowest water in memory.
So (to steal an expression from the late By HEK) "Who pulled the plug?"
"A combination of events happening at the same time -- or the wrong time, depending on your perspective," said Capt. Paul Titus, the man who compiles the Tides Tables for the Fishin' Fridays page in The Times-Picayune. Those events, in order of occurrence:
-- In mid-January we entered an annual period of extremely low tides in the northern Gulf of Mexico which runs roughly through mid-January. During these weeks, Titus said, the mean low tide averages almost a foot lower than normal which, in turn, makes the average high tide well below normal. (Conversely, annual periods of extremely high tides occur from mid-May through mid-June).
-- November also is the month when winter cool fronts begin blowing through, typically arriving on stiff northwesterly winds. Because our coast is a large, shallow bowl, these winds push even more water out of our marshes.
-- In a typical fall, cold fronts are preceded by stiff southerly winds pulled from the Gulf by the approaching pressure ridge, an event that can bring water back into the marsh. One such front came through Wednesday and Thursday and, sure enough, stiff southerly flow moved water in from the Gulf, and the tides shot up.
But most of this season has been a little different. A big norther the third week of November was followed by a series of smaller, dry cold fronts that produced little southerly flow.
"So, a few weeks back, we were already in this low-tidal period when we get that first big front," Titus said. "The water went out on that blow, but for a few weeks it never came back in because we never really had any thing coming from the south."
It was during that two-week period that anglers thought a historic natural event was under way.
How low did it get?
"I've seen the bottom of some ponds and bays that I've never seen before," said Mike Frenette of Venice-based Teaser Charters.
And in Hopedale, Capt. Glen Sanchez and friends were on a rescue mission for standard trout.
"That canal that follows the road down here was filled with baby trout that were trapped by the low water," Sanchez said. "Some guys went down there with landing nets and were scooping them up, crossing the road and dropping them into Bayou la Loutre. They saved hundreds of them.
"I can tell you I've never seen that happen before. "
And, of course, dozens of anglers were stuck on mud flats they never knew existed.
"Oh, we were getting calls," Sanchez said. "Guys were running across bays and lakes that always had enough water, and found themselves stuck. They just weren't prepared for this."
That lack of preparation, Titus said, rests partly with the systems available to present tide tables to the public. Unfortunately for anglers and other boaters, there is no official way to mark the arrival of the annual below-average tide period. That makes the range listings on the daily tide tables during the period a trap for anglers unaware of the event.
"When a guy sees the range is, say, 1.5 feet for a day during this period, he might be expecting the water to come up one-and-a-half feet -- but that won't happen because you're starting that 1.5 feet from a deficit," Titus said.
"So, before you go fishing during this period, you've got to take into account that everything is going to be lower. And that's before you even begin to factor in the effects wind will have on water levels in our shallow estuaries."
It also means you need to boat with caution even in familiar locations, carry a push pole and make sure your marine radio or cell phone is in good working order.
You might also carry a pair of chest-high waders, just in case stepping out of the boat to push becomes necessary.
That's what happens when someone pulls the plug in mid-November
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