SCHENECTADY — Emergency management officials have a three-fold strategy when it comes to the 17-mile ice jam in the Mohawk River: Watch, wait and prepare for the worst.
The ice jam now stretches from Rexford down to Crane Hollow, according to Union College professor of geology John Garver, who has been studying ice jams for more than 20 years.
He said this ice jam differs from past ice jams, particularly because of size.
“This is the biggest ice jam we’ve seen in decades,” he said.
The only solution, according to emergency management officials, can come from mother nature.
Britt Westergard, a hydrologist with the National Weather Service in Albany, said what needs to happen in order to avoid flooding “is a nice easy melt.” This means periods of slightly above-freezing temperatures during the day, a lot of sun, and slightly below freezing temperatures during the evening.
“That would help the ice to melt in place,” Westergard said.
In terms of a worst-case scenario, if the area gets unseasonably warm temperatures, coupled with rain and snow melt, the resulting rise in water could get the jam moving. That’s when flooding dangers rise.
Genesis of an ice jam
The ice jam formed after weeks of frigid weather that began at the end of December. According to Westergard, the Arctic temperatures caused thick ice to form in the river.
Then, a period of above-average temperatures — sometimes as warm as 60 degrees — combined with heavy rain and snow melt caused the river ice to break into large chunks and water levels to rise, Westergard said.
Rising water brought some flooding to Schenectady's Stockade neighborhood over the Martin Luther King Jr. holiday weekend, though it was considered minor and no evacuations were needed.
There was a second scare around Jan. 23, when a flood watch was issued by the National Weather Service as the river inched toward its flood threshold. The water then receded without flooding, but also without moving broken ice farther downriver.
The ice jam is being held in place because of minimal sunlight and below-freezing temperatures, according to Westergard.
Garver also said that, while it looks like a frozen mass, there is water flowing beneath the ice, which ranges in thickness from 2 to 15 feet, based on drone footage of the jam captured by the Albany County Sheriff's Department.
The drone missions were flown between Jan. 20 and Feb. 3, according to Inspector Lee Bormann, commander of the Albany County Sheriff’s Department’s Critical Incident Emergency Management Unit.
Albany County Sheriff Craig Apple said the drones also allow them to estimate how long it would take for flood waters to reach areas of Albany County, if there were to be a fast thaw.
“Our major concern on the Mohawk is the Colonie area and the high flow of water coming down into the Hudson [River] and disturbing river cities,” Apple said. “That would be a couple hours away, if we had a massive thaw.”
Apple said the use of drones has allowed views of the river and the ice jam that they normally wouldn’t have.
“You can put a drone in places where you can’t put a human — where they won’t get injured,” Apple said. “We’re able to measure things we weren’t able to measure before.”
State Environmental Conservation Commissioner Basil Seggos said his agency has also been flying drones over the river to monitor conditions.
“It’s something we’ve been looking at very closely and assessing any threats,” Seggos said.
In addition to drone footage, officials are watching data from the United States Geological Survey.
The USGS has four stations along the Mohawk to monitor water levels, according to Chris Gazoorian, a hydrologist with the USGS's New York Water Science Center. The center's main job is to collect data from the river and report conditions to local agencies.
The monitoring stations let Science Center officials compare the slope of the river during summer, spring and fall with the slope as ice clogs the river in the winter.
What the monitoring has shown this winter, in the area between Lock 8 and Freemans Bridge, is the ice in the channel has caused the water level to be 4.3 feet higher than it would be if there were no ice.
What can be done
There aren’t a lot of options for removing the ice jam.
Emergency officials have ruled out using icebreakers — large vessels that can clear frozen waterways — or other mechanical means. Seggos said the Mohawk too shallow for those options.
“There’s no opportunity for navigation,” he said.
Garver also said it doesn’t help that there's nowhere for the ice to go, even if it could be smashed up.
“With ice breaking, you do it where there’s room to move stuff out of the way, “Garver said. “But there’s nowhere for it to go.”
Seggos did say they are lowering the water level in the reservoir system to allow for more storage in the event of heavy rain or snow melt.
“That will help ultimately to slow down the amount of water that is flowing down the river,” Seggos said. “We’ll be able to parse that out over time.”
Monitoring and preparing
Though there may not be much that can be done to address the ice jam, city, county and state officials have been monitoring it and making preparations for flooding.
Division of Homeland Security and Emergency Services Deputy Director Nikhil Natarajan said that agency has been in constant contact with local officials about flood preparations. He also said agency staff check river levels on a daily basis.
“We are working with them right now to provide sandbags, sandbaggers — filled sandbags as well as empty ones — that can be used should the need arise to help shore up areas such as the Stockade and other areas that might be prone to flooding, as a preemptive measure, should we start to see water levels rise,” Natarajan said.
Joe McQueen, spokesman for Schenectady County, said an emergency preparedness team, composed of members from every department in the county, is also ready to assist with everything from crisis counseling to emergency housing for flood-affected residents.
“Every department has someone on the preparedness team because there are so many aspects that can occur [in an emergency],” McQueen said.
Schenectady Assistant Fire Chief Michael Gillespie said firefighters went door to door on Saturday in areas most prone to flooding to hand out fliers about what to do in an emergency. He also said they are taking headcounts on the number of pets and occupants in each home.
They also are looking at medical and utility problems that could arise if the city were forced to cut power to flooded areas.
“We want to have a strong database so we know exactly what we’re dealing with, with all the residents and all the houses,” Gillespie said.
Westergard said the forecast for the next few days is for temperatures that are good for a nice easy melt, though there isn’t much sun in the forecast.
Garver said conditions are right for the ice jam to remain in place through February. Now, the focus is on what will happen in March, barring a “freak warmout” this month.
“Either we’ll have a slow burn or we’ll have ... lots of rain and a huge amount of melt. That’s when we really have to keep an eye on what’s happening,” Garver said. “It’s a wait-and-see situation.”
What residents can do
City and county officials have asked residents using unlisted landlines or cellphones to sign up for the county’s emergency rapid notification call system.
Natarajan has also suggested residents attend the agency’s Citizen Preparedness Class on March 2, so they can learn what to do in case of flooding.
The class will take place from 9:30 to 11 a.m. in Schenectady County Community College’s Carl B. Taylor Community Auditorium.
The event is free and open to the public, and participants will receive free backpacks with emergency supplies inside.
Those who wish to attend can register at prepare.ny.gov/training-events.