So. Tier Topography Opens Area To More Major Floods

More

VESTAL, NY (WSKG) – A decade ago, the Southern Tier experienced historic rainfall and flooding, setting records that stand to this day. The frequency of these storms is increasing and the region is prone to more flooding.

“I Have Never Seen A River Rise So Quickly”

It was a wet summer and fall in 2011, as Tropical Storm Lee moved into the area colliding with the topography of our region and a cold front which stalled out the storm.

Dave Nicosia, a meteorologist with the National Weather Service (NWS) in Binghamton, said the storm rained itself out over the region, dumping up to 12 inches of rain in the hardest hit areas, such as Conklin, Binghamton, and Owego.

Aerial view of flooding in Binghamton. (Photo courtesy National Weather Service in Binghamton)

“The Susquehanna River came up so fast. I have never seen a river rise so quickly,” Nicosia said. “And it went over the top of the levies in many of our towns and cities along the Susquehanna in the Twin Tiers.”

Nicosia said the ground was already saturated before Tropical Storm Lee hit so the water had no place to go but into streams and the Susquehanna River.

“The topography around here, we have a lot of hills and valleys and our soils are prone to saturate very quickly. Our soils aren’t that deep and are full of rocks and clay – if you try to dig around here, it’s pretty difficult. So our soils saturate rapidly.”

The Flood Prone Twin Tiers

New York State’s Climatologist Mark Wysocki said the region is poised for another major flood event. It has been a wet summer, the ground is saturated and peak tropical storm season for the region is August and September.

Wysocki said the region is prone due to the focused complex topography. It has hills and valleys along with shallow streams that cannot take on large amounts of water. As storm systems hit these hills and valleys they get trapped, dropping large amounts of water. However, that water does not drop equally across the region, making flood forecasting difficult.

(Nancy Coddington/WSKG)

“You can get these focusing effects due to topography and, because we are considered in meteorological terms ‘complex topography’, it makes it even more focused. Where you might have one county that gets 4 inches of rain and the county next to it only gets half an inch,” Wysocki said. “And therefore, that creates localized flooding and is a nightmare for forecast centers.”

Radar from Tropical Storm Lee showed how rain bands set up across the region and became trapped within our hills and valleys.

In the last 25 years, these events are occurring more often and with higher precipitation amounts due to climate change. Like the snow storm that dropped more than 40 inches in parts of the area last year.

“Climate change is not gradual, People think one-tenth degree each year, each year. No, the earth’s systems; it’s atmosphere, ocean, and land, don’t work that way,” Wysocki explained. “It is very complex, we call it non-linear. Which means we get these extreme events and nothing and then extreme events and nothing, they occur with greater frequency.”

A People Problem

Humans have compounded the issue by building in harm’s way along floodplains and draining marshes that act like sponges. Marshes absorb large amounts of water and then release it over time, slowing the movement and momentum of water.

People have created impervious surfaces like parking lots that do not absorb rain.
Wysocki said building smarter using materials that let water drain through and into the ground would help, but it is more expensive.

In the future, Wysocki suggested communities should keep streams clear of debris, increase river monitors to assist with flood forecasting, and avoid building in flood prone areas.