As the largest estuary in North America, Chesapeake Bay is 200 miles long and at some points 30 miles wide. Over 130 rivers and streams empty into the estuary, defined as the water area where fresh water meets the salty ocean. Covering almost 4,500 square miles, Chesapeake Bay weather has sent many ships to the bottom of the bay, but it is the weather today and how it interacts with the greater environment that concerns conservationists.
Chesapeake Bay lies on the eastern seaboard of the United States and is enveloped by two states: Maryland and Virginia. Two major Maryland cities—Baltimore and Annapolis—are situated on the northwestern section of the bay. It flows into the Atlantic Ocean at its most southern extremity near the Virginia cities of Hampton, Norfolk and Virginia Beach. The 20-mile long Chesapeake Bay Bridge and Tunnel traverse the mouth of the estuary, connecting Virginia’s more remote northeastern shore with the rest of the state.
Chesapeake Bay weather, or better defined as “climate” or weather over time, varies greatly. At its far northern sections, the climate is continental with hot summers and cold winters. Southern sections near the Atlantic Ocean feature the more sub-tropical characteristics of very humid, hot summers and mild winters. Temperatures average 7 to 10 degrees higher in the southern sections. Average annual rainfall over Chesapeake Bay is 43 inches. The bay rarely freezes, and only in the northern region.
Weather events can affect water quality and wildlife. Hurricanes can pass over the area giving rise to tidal surges, heavy rain and floods. The area is prone to both excessive rainfall and severe droughts. Over half of the water volume in Chesapeake Bay is supplied from surrounding rivers, so area rainfall greatly affects the volume of water entering the bay resulting in varying water levels. Salinity also varies based on incoming fresh water from rivers. This can affect sea life that requires a certain level of salt concentration to survive.
The bay is shallow, and accordingly air temperatures quickly affect water temperatures. These can vary by up to 50 degrees Fahrenheit. High temperatures also deprive water of oxygen and can reduce growth of certain seaweeds. Compounding the effect, high temperatures spur algae growth, which reduces sunlight for other grasses. High winds also affect the bay, creating different mixes of salt and fresh water as water is “pushed” toward shore.
In the 70s, conservationists began to see changes in the bay, including a loss of habitat for some species. Oysters were not as plentiful, and some birds dependent on particular sea grasses for food left the area. Weather events coupled with fertilizers and toxic chemicals that flowed into the bay after heavy rainfalls polluted the waters. Substantive efforts are now underway to restore the bay. While recognizing weather events will continue, officials are now rebuilding watersheds and controlling run-off pollution to work with the “weather of the Chesapeake.”
