Hurricanes in Delaware River Basin
affect the USS Kawishiwi AO-146
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Hurricane Connie formed way out in the Atlantic on August 3, 1955, and headed west. By the morning of the 12th, hurricane warnings were issued as far north as the Delaware breakwater. Connie came inland in North Carolina, and headed straight for Delaware, but then veered left and passed over Chesapeake Bay. Still, winds gusted past 60mph in Philadelphia, and Connie soaked Delaware, eastern Pennsylvania, and New Jersey with 4 to 6 inches of rain. 

The soggy remnants of the storm continued northwestward into the Great Lakes. With this unusual track, we stayed in a southeasterly flow of warm moist air in the days after the storm, so the saturated ground didn't dry out much. And already, another tropical system was brewing in the Atlantic. 
While Hurricane Connie was racing past Delaware in mid-August 1955, another storm - Diane - was headed for the East Coast. Storm warnings were raised on August 16th from the Virginia Capes to Atlantic City. 

Diane came inland in North Carolina on August 17th as a minimal hurricane. It curved north and then east, passing almost directly over Wilmington as a weak tropical storm. Locally, winds from Diane only gusted to about 30mph, and rainfall was nothing spectacular, in the 1 to 3 inch range. 

But farther north in the Delaware River Basin, Diane dumped 6 to 12 inches of rain. With the ground still saturated from Connie's rains a few days earlier, the Delaware River flooded to record levels in many places - 22 feet above flood stage at Easton, Pennsylvania. The Schuylkill River also topped its banks, putting some Philadelphia streets underwater. 

But Diane's affect on our region was tame compared to New England, where it unleashed some of the heaviest rains ever recorded there. Damage estimates from the storm, adjusted to present-day dollars, ran into the billions, making Diane one of the 10 most expensive hurricanes ever to strike the United States. 
Kawishiwi remained in port due to the following reasons....
The port of Philadelphia is considered to be a hurricane haven, so remaining in port is the recommended action. The Penn and Parker terminals and the Reserve Basin provide suitable berthing during hurricane winds, provided prescribed measures to ensure protection of life and property are taken. Ships berthed at the Navy Yard finger piers that can be moved should be reberthed in the Reserve Basin. 
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The designation of Philadelphia as a hurricane haven is based on the following factors:
(1) Hurricane force winds associated with tropical cyclones are extremely rare in the Philadelphia area. The only occurrence during the 37-year period 1943-1979 was during Hurricane Hazel in 1954 when maximum peak gusts to 82 kt were recorded at the International Airport.

(2) The distance inland by direct route or along the Delaware Bay/River estuary greatly reduces the energy of the wind and hence its capacity to create water waves, as compared to the energy level in tropical cyclones when they first make landfall.

(3) Evading to the open ocean is a high risk action because:

(a) Under normal conditions it is a 5 to 5 1/2 hour passage from Philadelphia to the open Atlantic. 
(b) The orientation of the coastline in the vicinity of the mouth of Delaware Bay allows only two alternatives once the open ocean is reached: head east and cross the likely track of the storm, or head northeast and try to outrun the storm. Neither is a preferred option. 
(c) The 24- and 48-hour mean forecast tropical cyclone position errors are large, approximately 120 and 360 n mi (see General Guidance, Figures I-3 and I-4). Thus decision making becomes even more difficult once the open ocean is reached. 
5.2 RUNNING FOR SHELTER
Ships at sea should give due consideration to their distance from the open ocean and the space restrictions of Philadelphia's river-type port before considering running to the Port of Philadelphia for shelter. However, the lower Delaware Bay provides more direct access from the open ocean and some shelter from high winds and seas. The Lower Bay historically has been used as an anchorage area during occurrences of hurricane force winds.

The universal advice for preparing small craft for hurricane force winds is to remove them from the water or bottom moor them. The next best action is to move them into the smallest bays or tributaries possible and allow for extreme tidal and flooding conditions. During the passage of Hurricane Connie in August 1955, the high water level exceeded the normal high tide level by about 4 ft. Table XVII-2 shows that a storm surge of 5 ft occurred with the passage of Connie; this storm surge apparently occurred near the time of high tide, resulting in the high water level. There are no recommended small craft mooring facilities in the main harbor of Philadelphia (Delaware River channel).
 
After the 1955 floods claimed 90 lives and caused $100 million in damage in the Delaware River Basin, Philadelphia District did the nation's first comprehensive basin study. It led to building five flood control dams in eastern Pennsylvania -- Beltsville and Blue Marsh Lakes, Francis E. Walter Dam, Prompton Dam, and General Edgar Jadwin Dam. 

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