Extreme Water Levels during the 2020 Hurricane Season
Summary
The 2020 hurricane season was the busiest, most impactful season in the Atlantic with a record-breaking 30 named storms. NOAA's Center for Operational Oceanographic Products and Services (CO-OPS) tracked the water levels during these storms in real-time through CO-OPS’ Coastal Inundation Dashboard web mapping tool. This tool allows users to monitor elevated water level conditions along the coast when a tropical storm or hurricane watch or warning is issued.
Throughout the season many CO-OPS water level stations measured record or near-record water levels. Most of the significant water level events were recorded during four storms: Hurricane Hanna, Hurricane Laura, Hurricane Sally, and Hurricane Zeta.
2020 Atlantic Hurricanes. Storms that did not make landfall along the U.S. coast appear as lavender lines. The thirteens storms that did make landfall along the U.S. coast are symbolized by storm type.
Hurricane Hanna
July 23-26
Hurricane Hanna was the first hurricane to make landfall in the United States during the 2020 hurricane season.
Hanna formed over the central Gulf of Mexico and tracked westward, intensifying to a category 1 hurricane and making landfall in Texas with maximum sustained winds of 90 mph.
4 Kilometer Resolution Infrared GOES Satellite Imagery Animation
Hurricane Hanna making landfall in Texas from the GOES-16 (GOES-East) satellite on July 25, 2020.
Peak observed water levels above MHHW (ft) during Hurricane Hanna (map on the right)
- Record high water levels: 5.48 feet above Mean Higher High Water (MHHW) at Bob Hall Pier, Corpus Christi, TX . MHHW represents the average highest tide in a day at a location. This is a new record for the station surpassing the previously held record during Hurricane Ike in 2008 (4.32 feet).
The plot above shows peak water level observed at Bob Hall Pier, TX during Hurricane Hanna.
Bob Hall Pier in Corpus Christi, TX upgrade in 2017.
This National Water Level Observation Network (NWLON) station, which was installed at the current location on 5/19/1989 and upgraded in 2017 (image above), survived the storm despite damage to Bob Hall Pier.
The video below by Live Storms Media shows the extent of pier damage.
Bob Hall Pier Damage (credit: Brian Emfinger / Live Storms Media)
Several other CO-OPS stations also recorded significant elevated water levels (image below) including:
- Aransas, Aransas Pass, TX - 3.29 ft above MHHW, station established in August 2016. This station also experienced top-ten water levels on record this hurricane season during Tropical Storm Beta, Hurricane Delta and Hurricane Laura.
- Port O’Connor, Matagorda Bay, TX - 3.06 ft above MHHW, station established in January 1989. This record was later superseded by Tropical Storm Beta on 9/22/2020 - 3.53 ft above MHHW.
- USS Lexington, Corpus Christi, TX - 3.76 ft above MHHW, station established in January 2004. This station also experienced top-ten water levels on record this hurricane season during Tropical Storm Beta and Hurricane Delta.
Observed water level during Hurricane Hanna
For further information on impacts of Hurricane Hanna Please click the link below.
Hurricane Laura
August 20-27
Hurricane Laura began as Tropical Depression Thirteen on August 20, east of the Windward Islands. After reaching tropical storm strength, Laura moved across the , resulting in water levels that peaked under a foot above MHHW.
Peak observed water levels above MHHW (ft) during Hurricane Laura (map on the right)
Once Laura reached the eastern Gulf of Mexico on August 25, the storm began to rapidly intensify to a category 4 hurricane over the next 36 hour before making landfall near Cameron Parish, Louisiana on August 27.
GOES EAST image of Hurricane Laura on August 27, 2020
Water levels reached an incredible 9.19 feet above MHHW at Calcasieu Pass , which is located very close to the landfall location at Cameron Parish, LA. This is the second highest water level on record at this location behind the 10.01 feet above MHHW observed during Hurricane Ike (2008). The station was first established in 1933 and has been at its present location since 2002.
Record water levels were set at two stations in Lake Charles, LA, roughly 30 miles north of landfall:
This water level plot shows the maximum water levels (in feet above MHHW) recorded at the three stations labeled on the map. The rapid change in water levels is a result of storm surge from Hurricane Laura.
Calcasieu Pass is a NOAA Sentinel observing station that is reinforced to withstand hurricanes up to Category 4 and other major storm events.
Initial analysis by the National Hurricane Center (NHC) indicates that the highest storm surge from Laura may have actually been a little farther to the east of the landfall location. Unfortunately, the next CO-OPS’ station to the east, Freshwater Canal Locks, LA , was completely swept away by the combination of wind and storm surge and failed to record a peak water level during the storm. Based on a nearby U.S. Geological Survey (USGS) water level station, it is estimated that this location also experienced water levels exceeding 9 feet above MHHW.
Click below to view before and after images from NOAA's National Geodetic Survey of the damage Hurricane Laura caused to coastal communities.
Hurricane Sally
September 11-16
Hurricane Sally began as a tropical disturbance east of the Bahamas that developed into Tropical Depression Nineteen on September 11. The depression initially made landfall along the Florida Keys at Key Biscayne and strengthened into a tropical storm as it moved northwestward into the Gulf of Mexico. On September 16, Hurricane Sally made landfall at Gulf Shores, AL with 105 mph winds becoming the first hurricane to make landfall in Alabama since Ivan in 2004.
GOES EAST image of Hurricane Sally on September 14, 2020
Water levels reached 5.6 feet above MHHW at Pensacola, FL . This was the third highest water level ever recorded for this station, which was first established in 1923 and has been at its current location since 1996, trailing only Hurricane Ivan (2004) and the 1926 Miami Hurricane.
Peak observed water levels above MHHW (ft) during Hurricane Sally (map on the right)
However, it was not the storm surge that was the most interesting impact of Hurricane Sally, but the extreme low water levels observed to the west of landfall within Mobile Bay.
Peak observed water levels below MLLW (ft) during Hurricane Sally (map on the right)
As Hurricane Sally passed to the east, strong winds from the north pushed water out of Mobile Bay. Several stations observed this "draw-down" as illustrated in the water level plot below.
This water level plot shows the minimum water levels (in feet relative to MLLW) recorded at six stations in Mobile Bay labeled in the map. The rapid drop in water levels is from Hurricane Sally pushing the water out of the bay.
At Coast Guard Sector Mobile, AL , water levels dropped to 6.99 feet below Mean Lower Low Water (MLLW). MLLW represents the average lowest tide in a day and is commonly used for navigation. Observed water levels at three other stations in Mobile Bay ( Chickasaw Creek, AL ; Mobile State Docks, AL ; and Weeks Bay, Mobile Bay, AL ) measured this negative storm surge, but dropped so low that a minimum was unable to be measured.
A tweet from NOAA's Ocean Service noting the preliminary water levels recorded as Hurricane Sally made landfall.
How much damage was caused? Click below to view imagery from NOAA's National Geodetic Survey of damage from Hurricane Sally.
Hurricane Zeta
October 26-29
Hurricane Zeta developed over the Western Caribbean Sea, slowly moved westward and emerged into the southern Gulf of Mexico as a Tropical Storm. It turned northeast and strengthened to a hurricane on October 28, 2020 . The storm made landfall as a category 2 hurricane with a peak intensity of 110 mph along southeastern Louisiana.
Zeta viewed by GOES East on October, 28, 2020, as it makes landfall at Cocodrie, Louisiana.
Peak observed water levels above MHHW (ft) during hurricane Zeta (map on the right).
As it approached, NOS/CO-OPS communicated with the public, tweeting the following:
A tweet from NOAA's Ocean Service noting the preliminary record water levels recorded as Hurricane Zeta made landfall.
Record High Water Levels: Zeta resulted in significant water level impacts from Mississippi to Mobile Bay with several stations hitting new records.
Observed water level during Hurricane Zeta
- Bay Waveland Yacht Club, MS : 8.16 ft above MHHW. This is the highest water level observed during Hurricane Zeta. This value is the second highest for the station following the peak observed value during Hurricane Gustav (2008).
Records previously held by Hurricane Nate (2017) at the following stations were broken.
- Pascagoula NOAA Lab, MS - 7.08 ft above MHHW, station established in September 2005.
- B ayou La Batre Bridge, LA - 6.89 ft above MHWW, station established in April 2011.
- West Fowl River Bridge - 5.92 ft above MHHW, station established in April 2011.
- Mobile State Docks, AL - 5.16 ft above MHHW, station established in September 2005.
National Geodetic Survey (NGS) collected aerial images in the aftermath of Hurricane Zeta. Collected images are available to view through the link below.
More Information about CO-OPS
NOAA's Center for Operational Oceanographic Products and Services is the authoritative source for accurate, reliable, and timely tides, water levels, currents and other oceanographic information. For more information, please see below.
