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Environment

2020 Atlantic Hurricane Season Review

Summary:

An active 2020 summer storm season passed by Anna Maria Island with minor effects. Hurricane Eta caused a surprisingly high storm surge and flooding overnight coinciding with a high tide. A local business man died from electrocution after touching a flooded appliance.

  • Above average storm activity
  • No Anna Maria Island evacuations
  • 2 landfalls on Florida Gulf Coast, Sally and Eta
  • Minor damage from Eta 2′ surge, which flooded some low-lying Anna Maria Island properties. Minor squalls and rainfall.
Fastest growing storms of 2020
US Mainland landfalls 2020

“I think really what stood out to me about 2020 was the extremely active late season. October and November were extremely active with seven storms and a whopping four major hurricanes (Delta, Epsilon, Eta and Iota).” said Phil Klotzbach, lead author of the forecast at CSU.

The causes of the active year, according to NOAA’s lead seasonal hurricane forecaster Gerry Bell, included warmer-than-average Atlantic sea-surface temperatures and a stronger west African monsoon, along with wind patterns coming off Africa that were more favorable for storm development. 

“These conditions, combined with La Niña, helped make this record-breaking, extremely active hurricane season possible.”

While it’s clear warmer ocean temperatures make storms stronger, there’s still vigorous debate among top climate scientists on the question of whether warmer waters lead to a greater number of tropical systems. 

 “My colleagues and I feel that the jury is very much out on the topic of global tropical cyclone frequency,” said Dr. Kerry Emanuel from MIT, a leading researcher on how climate change affects hurricanes. While this Atlantic season was extreme, he points out that what we see in the Atlantic Basin is not representative of the rest of the globe. “Only about 12 percent of the world’s tropical cyclones occur in the Atlantic, and globally it has not been a very exceptional year.”


Atlantic Hurricane Season
 April 2020 forecast 2020 Actual
Named storms (>35mph)       13  30
Hurricanes (>72mph)        8  13
Major hurricanes (>111mph)        4  9
US landfall likelihood    55%  40% (12)
Gulf Coast landfall    32%  30% (9)
Florida landfall 7% (2) Keys and panhandle

The Named Storms of 2020:

NameActive PeriodPeak Strength
mph
TS ArthurMay 16-1960
TS BerthaMay 27-2850
TS CristobalJune 1-1050
TS DollyJune 21-2445
TS EdouardJuly 4-645
TS FayJuly 9-1160
TS GonzaloJuly 21-2565
Hurricane HannaJuly 23-2790 (Cat 1)
Hurricane IsaiasJul 28-Aug 585 (Cat 1)
TS JosephineAug 11-1645
TS KyleAug 14-1650
Hurricane LauraAug 20-29130 (Cat 4)
Hurricane MarcoAug 20-2575 (Cat 1)
TS OmarAug 31-Sep 540
Hurricane NanaSep 1-475 (Cat 1)
Hurricane PauletteSep 7-23105 (Cat 2)
TS ReneSep 7-1450
Hurricane SallySep 11-18105 (Cat 2)
Hurricane TeddySep 12-24140 (Cat 4)
TS VickySep 14-1750
TS BetaSep 17-2560
TS WilfredSep 18-2140
TS AlphaSep 18-1950
TS GammaOct 2-670
Hurricane DeltaOct 4-12145 (Cat 4)
Hurricane EpsilonOct 19-26115 (Cat 3)
Hurricane ZetaOct 24-29110 (Cat 2)
Hurricane EtaOct 31-Nov 13150 (Cat 4)
TS ThetaNov 10-1570
Hurricane IotaNov 13-18160 (Cat 5)
Hurricane Laura track
Hurricane Laura track August 20 – 29, 2020, becoming Cat 3 near landfall
Tropical Storm Isaias July 28 – August 5, 2020
Hurricane Delta October 4 – 12, 2020
Hurricane Zeta October 24 – 29, 2020
Hurricane Zeta wind field October 28, 2020
Tropical Storm Eta tracked west into central America causing widespread damage then returned east to cause havoc to Cuba, the Keys, and then north off the Florida west coast as Cat 4 hurricane October 24 – 28, 2020, weakening at time of landfall.

For detailed discussion of factors contributing to 2020 storm weather, see CSU meteorology (pdf).

Categories
Environment

Hurricane Hermine Hits Holmes Beach Hard

Ficus blown over by wind gust. Culverts did not drain.
A Ficus tree blown over by a wind gust. Culverts did not drain.

On August 18th, a weather disturbance in the Atlantic Ocean formed into an area of tropical interest and labelled “Invest 99L” by meteorologists. For ten days it crept across the ocean and meandered in the eastern Caribbean. By Monday August 29th, Tropical Depression 9 hatched, and unconstrained by prior nearby steering winds headed into the Gulf of Mexico to become Tropical Storm Hermine on Wednesday.

Hurricane Hermine path
2016 TD9 in Florida Straights becomes Tropical Storm Hermine, then Hurricane Hermine at landfall.

West Florida went on high alert. Storms this close sometimes run up the coast like Tropical Storm Debby (2012), sometimes change direction suddenly or quickly intensify like Hurricane Charley (2004). In any case Hermine looked like it would be a rain-maker like Tropical Storm Colin earlier this year.

Blocked drain and overwhelmed percolation pits.
Blocked drain and overwhelmed percolation pits.

Anna Maria Island residents experience nature’s best and worst conditions. Summer storms can be brief and invigorating or inconvenient and terrifying. Hermine kept offshore but the effects stayed around for 3 days, tossing 9″ of rain, 45mph wind bursts, frequent lightning and massive thunder booms from waves of storm-bred feeder bands.

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Combined with 2½ feet of surge on top of 2½ foot high tides, torrential and long-lasting rainfall overwhelmed the newly installed “percolation” pit drainage, causing what many people described as the worst flooding they have ever seen on the island. Schools closed Thursday, roads became impassable, and sewers backed up. Power stayed on apart from a short outage when a falling tree brought down some lines.

Categories
Environment

Tropical Storm Debby Flooding

Tropical Storm Debby formed off the Gulf Coast June 23 northwest of Tampa with a poorly defined center and no obvious direction of travel. But as the wind field grew wider while it remained almost stationery, the effects of the tropical moisture with persistent rainfall and wind wore away the resistance of beaches and its inhabitants.

By Monday June 25, constant battering by 20 – 40 mph wind and 10″-16″ of rain took its toll on shorelines and low lying property. Combined with high tides, a 2-3 foot storm surge poured over seawalls, rose up through storm drains and flooded streets and yards. Tropical Storm Debby wind field

Saturated ground had nowhere to drain. Streets and yards remained covered with water even as the tide dropped but the surge raised the sea-level. Onshore wind pushed the sea state higher over the shore. Softened soil and gusty winds uprooted some trees and sent limbs and palm fronds flying.