Coastal Change During Hurricane Dennis 2005

Hurricane Dennis made landfall as a Category 3 storm on Santa July 12, 2005 - Post-Dennis Rosa Island in the Pan- handle on July 10, 2005. Ex- posed to some of the strongest winds, Santa Rosa Island suffered erosion, as well as severe over- wash. A of 2 m was recorded near Navarre Beach. The U.S. Geological Survey (USGS) and U.S. Army Corps of Engineers (USACE) are col- laborating in a research project investigating coastal change that occurred as a result of Hurricane Dennis. The USGS acquired still oblique aerial photography both before and after hurricane landfall to better understand the impacts of extreme storms on coastal environments. On Tuesday, July 12, 2005, scientists conducted an aerial photographic survey of Santa Rosa Island, Florida, that was impacted by Hurricane Den- nis. The photographs were com- pared to pre-Dennis photographs taken in July 2001 and after the landfall of in Sep- tember 2004 to illustrate extreme coastal change. On Santa Rosa Island, the storm eroded dunes and beaches, and overwashed roads. In Navarre Beach, parking lots and roads were covered with sand and dune walkovers dam- aged or destroyed.

Area Florida Shown Pensacola Figure 2 Figure 3

and Figure 4 Rosa Isl Navarre Santa Beach

Pensacola Beach Kilometers Path of Dennis 0 10 Figure 2. Santa Rosa Island, Florida, suffered severe erosion and overwash during Hur- Figure 1. Map showing track of Hur- ricane Dennis. Looking east, the magnitude of the overwash is evident. Overwash fans ricane Dennis in 2005 across Santa Rosa extend northward across the island, covering roads with sand eroded from the beach Island, Florida. and dunes. In some cases, the overwash extends into the back bay.

U.S. Department of the Interior Printed on recycled paper Fact Sheet 2009-3027 U.S. Geological Survey March 2009 July 17, 2001 July 17, 2001

September 19, 2004 - Post-Ivan

September 19, 2004 - Post-Ivan

July 12, 2005 - Post-Dennis July 12, 2005 - Post-Dennis

Figure 3. Navarre Beach, Florida. On this part of Navarre Figure 4. Navarre Beach, Florida. Overwash during Hurricane Beach, overwash deposits from Hurricane Dennis extend farther Ivan covers the parking lot and road with sand. Overwash from landward than overwash deposits from Hurricane Ivan. De- Hurricane Dennis covers the parking lot with sand, but does not posits from both storms covered the two coast-parallel roads. extend as far inland as did the overwash during Hurricane Ivan. (Arrows in all images point to the same features.) A section of the pier is missing following landfall of Hurricane Dennis. (Arrows in all images point to the same features.)

Author: Karen L. M. Morgan, USGS [email protected] 727-803-8747 x 3037 Project Contact: Asbury (Abby) Sallenger, USGS [email protected] 727-803-8747 x 3015 http://coastal.er.usgs.gov/hurricanes/