meteorology

Seasons of the swamp
And where we're at now

Meteorologically the swamp has two seasons …

The wet season (May to mid October) and the dry season (November into May.)

Not your typical four seasons, but four nonetheless

But terrestrially the swamp sees four seasons on the ground.

1.Soaking in season. The early part of May is usually the crunchiest time of the year to walk through the swamp: water is absent except in the deepest pools. By month’s end the wet season will have started, followed by June – the rainiest month of the year; yet only rarely do waters peak this early. Late May through June is usually a “soaking in” season for the preserve.

2. Sheetflow season. The onset of summer, lasting into early fall, coincides with an extensive but ephemeral sheet of shallow flowing water in the swamp. Its flowing aspect is achieved when waters rise to the base of the hydric pinelands (i.e., a depth of 20 inches in the pond apple swamps) and higher. The depth, spatial extent and flow rate of sheetflow typically peak between late August and early October.

3. Hydrologic Interregnum. Starting with the demise of sheetflow in mid fall and lasting through winter is the hydrologic interregnum. This is an approximate five month period in which “wet season” water is still present on the ground, but atmospherically the “dry season” has set in, thus initiating the slow demise of the swamp’s expansive sheet of surface water. The duration of surface water in any one spot is largely habitat dependant, but may also be sustained by winter rains, particularly during El Niño years. Pinelands go dry first, followed by marl prairies which eventually leads to a retreat of waters into the tall cypress and pond apple swamp.

4. Spring drought. The swamp ebbs to its low water mark in April and May due to the cumulative effect of months with little rain and increasing rates of evapotranspiration (rising temperatures, expanding hours of daylight, and plant transpiration). During this period, surface water is practically absent from the swamp other than smallish (typically less than an acre) and isolated pools called dry season refugia.

The above chart shows the relation of south Florida’s two meteorologic seasons, i.e. wet and dry, with the landscape hydrology of the swamp.  The typical duration of flooding in major swamp habitats is also shown.

What season are we currently in?

Answer: Winter dry season (meteorologically) but still high up in “hydrologic interregnum” season (terrestrially).

The “spring drydown” season will be delayed and most likely short, if at all — but I wouldn’t rule out one yet.

dry season

Summer sputters to end
Who keeps turning on and off the switch?

It’s a long summer in south Florida …

And then suddenly like a flip of a switch the rains stop.

The regular pattern of afternoon rains stops in early October

At least that’s how it seemed a week ago.

The late September slug of air had us convinced the summer rain machine had shut down for the year. Ten days later more humid air has returned, and the rain machine has even shown some signs of life. But the bigger picture is it’s starting to sputter off. Usually by Columbus Day (early-mid October), the winter dry season has begun even if from a monthly book-keeping sense we wait until November 1st to start the official dry season clock.

big weather

Steaming swamp
Think hot asphalt after a cool rain

From the distance it looked like smoke …

Or maybe dust kicked up from the limerock road.

It looked primordial, but it was actually super chilled

Only upon closer inspection did we see it was steam.

The source?

Similar to a hot asphalt road steaming after getting cooled down by an afternoon shower, the wisps of water vapor hovering over the cypress stand were the result of an ice-cold drenching from a super thunder cell.

The super cell, looking north, about 15 mile east of the strand

As good fortune would have it, I actually took a photo of the thunderstorm about an hour before and 15 miles upwind from the steaming strand. The air among the wisps was incredibly cooled and the fragrance from the cypress intense. Landing and walking in the water was further proof.

The water was chilled as if it had hailed.

Seize the rainbow

As a meteorological phenomena …

Rainbows never cease to amaze.

Here one minute

But you better look quick, because they do disappear

Less than a minute after taking the photo above …

Gone the next

The rainbow was gone.