By Dr. Robert Thorson

An orange armada floated down the Connecticut River last week. Heavy rains on upriver farms sent a fleet of pumpkins downstream to smiling boaters photographed by The Courant during the unusual rescue event.

Within a few days, New England’s attention had shifted away from happy people collecting pumpkins in the river to the unfolding flood disaster caused by record-breaking rains. Residents were killed by raging floodwaters, raw sewage poured into both Boston Harbor and Narragansett Bay, dozens of towns and cities were damaged and the entire flood-management infrastructure was put on high alert.

In retrospect, the pumpkin flood was a forecast of things to come. I first heard the term “pumpkin flood” several years ago from a historian in South Windsor who couldn’t tell me the origins of the term. I investigated a bit. The earliest mention I found was of a pumpkin flood in 1753 at Harpers Ferry, Va., where the Potomac and Shenandoah rivers meet. Two more pumpkin floods occurred during the 1780s, one on the Susquehanna River in New York and the other somewhere in New England from the Connecticut River.

Surprisingly, I could find no mention of the term in the authoritative Encyclopedia of New England, recently published by Yale University Press. Apparently, as our culture shifted toward industry and our understanding of flood meteorology improved during the 19th and 20th centuries, the quaint term “pumpkin flood” receded into folk wisdom.

I recommend resurrecting it, not to improve our highly sophisticated flood-warning system, but to improve the way that information is communicated to the public.

New Englanders typically connect flooding with springtime, not autumn, when in fact the threat of fall floods is very real. Pairing “pumpkin” with “flood” will help correct this unfortunate misconception.

Large Northeastern rivers are bipolar with respect to their flood regimes. Spring floods commonly occur from heavy rains that combine with snowmelt. Cold brown water, often decorated with ice chunks, is the result. Fall floods are caused by the drenching moisture of tropical storms that are most frequent near the end of the hurricane season. Warmer, clearer water with bobbing pumpkins can result.

Only the strongest tropical storms reach hurricane status. But each one is sopping wet with evaporated moisture. The storms act like pin-wheeling sponges, wringing themselves out over the land.

Most careen westward into the Caribbean and Gulf Coast landscapes. But some turn northward and migrate up the Atlantic coast, full of potential drench. When these storms stall over or slowly migrate through New England, the terrain is soaked into submission precisely when pumpkins are lying in the fields.

At first, each pumpkin simply gets wet. Then the floodwaters rise, covering the pumpkin’s bottom. But just before it’s submerged completely, a pumpkin floats skyward and reaches the end of its tether, resembling an orange lobster buoy being dragged by a rising tide. If the floodwaters keep rising, fields of pumpkins are uprooted from the saturated ground. Then, with anchors cut, a pumpkin fleet is swept downstream. Thousands of spherical ships then bobble like enormous tangerines in muddy water, dragging their twisted stalks behind them, announcing to everyone that a lingering wet tropical storm is doing its October thing and might just get worse.

Think about the potentially useful information being conveyed by a pumpkin flood, whether for historians or watchful modern residents. Each tells us that at least one well-drained upriver floodplain was submerged by several feet of water. Each tells us that the river was recently rising, because that’s what it takes to lift an orange armada from dry dock. Finally, each pumpkin flood reminds us that October is a month when the flood hazard is statistically high.

New England’s flood season won’t be over until the jack-o’- lantern candles are all safely blown out