Tropical Storm — St. Johns, Florida

2016-10-06 to 2016-10-08 · St. Johns, Florida

Event narrative

Tropical storm force gusts began in St Johns county Thursday night on 10/6. At Vilano Beach winds were reported at 39 mph with gusts to 46 mph at 11 pm. Hurricane force gusts were reported near the coast on 10/7. The CMAM (SAUF1) site on the St Augustine pier reported a 79 mph gust at 11:50 am and 86 mph (75 knot) peak gust at 1:28 pm on 10/7. Guana River State Park reported a 72 mph gust at 1:45 pm and the Vilano Beach Bridge had a 60 mph gust.

The peak sustained wind measured at the St. Augustine Airport was 51 mph on 10/7 at 1:21 pm. The peak gust at this location was 68 mph on 10/7 at 2:18 pm. The peak sustained wind measured at the WeatherFlow sensor at Crescent Beach Summerhouse was 56 mph on 10/7 at 1:25 pm. The peak gust at this location was 75 mph on 10/7 at 1:45 pm. The peak sustained wind measured at the WeatherFlow sensor at Lewis in St. Johns was 45 mph on 10/7 at 1:59 pm. The peak gust at this location was 67 mph on 10/7 at 1:09 pm. The peak wind gust measured 1 mile NW of Fruit Cove was 39 mph on 10/7 at 2:55 pm. The peak sustained wind measured at the SAUF1 CMAN Station in St. Augustine was 66 mph on 10/7 at 1:30 pm. The peak gust at this location was 86 mph on 10/7 at 1:28 pm. The peak sustained wind was 47 mph on 10/7 at 12:30 pm at the NERR station at the Guana Tolomato Mantanzas reserve.

Wind damage reports included a tree uprooted onto a home in St Augustine Shores around 8 am and significant roof damage to First Coast Powersports off U.S. Highway 1. A large tree fell on San Marco Ave near Hope Street in St Augustine. On Interstate 95 near International Golf Parkway, a tree blocked one lane.

Storm surge flooding was severe as a NWS storm survey reported a new inlet had formed between Marineland and Matanzas inlet. The NWS storm survey estimated storm surge heights of 6 to 7 feet above ground level along old A1A in the vicinity of the new inlet near Summerhaven. Severe damage was reported in Summerhaven as well as Matanzas inlet with many houses and several businesses inundated with water of at least 3 feet deep.

Storm surge flooding was reported in the early morning hours at the sea wall in St Augustine Beach and at the Castillo de San Marcos sea wall. Average water depth was from 2.5 to 4.0 feet above ground level in the city of st. Augustine, with the greatest depths in that range occurring along the bay front and also along the San Sebastian river. Water was also reported flowing across Anastasia Island at about 2.5 feet above ground level.

The following sites reported a peak storm tide, datum MHHW: Old A1A near Summerhaven 6 ft MHHW; Treasure Beach 7.0 ft MHHW; Mantanzas Oceanfront 7.0 ft MHHW; Ft. Matanzas Oceanfront 7.0 ft MHHW; St. Augustine Beach 6.0 ft MHHW; Butler Beach Intracoastal Waterway 6.0 ft MHHW; Davis Shores Bayfront 5.0 ft MHHW; Conch House 3.0 ft MHHW; St. Augustine Bayfront 5.0 ft MHHW; Castillo de San Marcos 4.0 ft MHHW; Lincolnville 5.0 ft MHHW; Vilano Beach 6.0 ft MHHW; Guana River Research Center 4.5 ft MHHW; and at the Ft. Matanzas National Monument 7.0 ft MHHW.

Major to extreme beach erosion was reported along the coast northward to Mickler's Landing. In many areas the dunes were cut back to 30-40 ft. In Ponte Vedra Beach, storm surge moved the sand dune line back 30 to 40 feet and eroded the dunes vertically such that there are now 12 to 16 foot cliffs at the edge of the dunes. This extreme erosion undermined numerous structures along the beachfront in Ponte Vedra Beach. Large rocks were uncovered on the beach and moved up to 150 ft back to state road A1A and major sand wash occurred in Marineland, Summerhaven, Vilano Beach, and South Ponte Vedra Beach.

The NOAA tide gauge on the St Johns River at Racy Point reported a surge of 5.20 feet above ground level with a storm tide of 4.55 ft on 10/7 at 6:36 pm. The Tolomoto River recorded a surge of 3.61 ft agl with a peak storm tide of 5.55 ft on 10/7 at 3:54 pm.

Inland flooding included major levels at Deep Creek in Spuds where a storm tide of 5.72 ft NAVD88 datum was recorded on 10/8 at 12 am.

Storm total 48 hour rainfall included: 9.97 inches 3 miles NNW of Bakersville; 7.48 inches 2.1 miles SSW of St. Augustine South; and 4:25 inches 1 mile NW of Fruit Cove.

Thus far about $2 billion in storm damages across the county.

Wider weather episode

Category 3 Hurricane Matthew track northward along the Florida Atlantic Coast Thursday October 7th, and then NNE remaining about 50 east of Mayport at the closest approach Friday morning October 8th. Northeast Florida and Southeast Georgia only experienced tropical storm conditions with sustained speeds generally 35-55 mph with higher gusts up to 80 mph along coastal areas and the St. Johns River basin, with much weaker winds inland. Strong winds and flooding rainfall, as well as a 4-7 ft storm surge impacted much of coastal NE Florida and portions of SE Georgia. Storm total rainfall amounts ranged from up to near 10 inches in some coastal and St. Johns River basin counties...down to only 2-4 inches farther inland toward the I-75 corridor.

Water levels were already elevated along the St. Johns River for several days ahead of Matthew due to a local nor'easter. Water levels were very slow to drain out of the St. Johns River basin with major to moderate flooding ongoing for about 5-6 days in portions of Putnam and St. Johns counties due to the seiche affect and water being trapped in the estuary under persistent onshore flow after Matthew.

Source: NOAA Storm Events Database, event_id 659430. Narrative written by the NWS forecast office that issued the report.