Vents, Roofs A Concern
Emergency officials are reminding residents to rake their roofs and keep their homes’ vents unblocked as forecasters predict more precipitation — including rain that could weigh down already snowy roofs — will blanket the Upper Valley early this week.
“As far as roof collapses go, it’s pretty early in the winter to be getting really worried about that for us, but when Monday comes around and we start getting rain, that increases the weight of snow exponentially on a roof, not to mention causing ice, which has a tendency to affect a structure once it starts moving around,” said Hartford Fire Capt. David Rowlee.
“If we had a normal winter like we used to have 30 years ago it wouldn’t be a big deal,” Rowlee said, “but when we get two feet of snow and then a day of real rain,” then the risks increase.
Although residents are advised to take precautions to prevent weight build-up on their roofs, Rowlee said a more common concern these days is carbon monoxide poisoning. While you can “count on one hand” the number of times his department has responded to structural collapses because of snow build-up in the past five years, he said, the squad responds to suspected carbon monoxide leaks inside homes two or three times a week during the winter. On average, one of those calls turns out to be a true leak, he said.
He stressed that residents should keep ventilation ducts clear from snow and ice and keep carbon monoxide detectors running, as carbon monoxide is odorless, colorless and mixes well with air.
“Part of the issue that we’re seeing these days is there’s a lot of technology out there for heating appliances that are a direct vent or something like that, that doesn’t need a chimney, so they’re exiting the home on a ground level, so you can really see issues … that they can ice over,” he said.
“Carbon monoxide detectors are saving peoples lives every day,” he said. “People say, ‘It’s going off and we don’t know why, there’s nothing wrong.’ ”
Greg Hanson, a meteorologist with the National Weather Service in Burlington, said the Weather Service is forecasting snow or a rain-snow mix this morning in White River Junction and surrounding areas.
The precipitation is expected to transition to light snow mid-day before turning into all rain tonight through Monday morning.
At some point on Monday, Hanson said, a cold front will move through the area and change everything back to snow by the afternoon.
Temperatures will top out in the low 40s Monday morning before dropping back below freezing around 4 or 5 p.m., he said.
“The good news is we will see some warmer temperatures and hopefully (that) will melt some of that snow and ice off people’s roofs, but it’s tough because all that ice is pretty massive and it has to warm up quite a bit before it starts melting, so I don’t think we’ll lose all the ice,” he said.
Hanson said that a variety of factors can affect how snow reacts to rain. In many cases, snow acts like a sponge and absorbs water, he said, dramatically increasing its weight.
Plus, “snow is a good insulator,” he said, “so even if the temperature warms up to 45 degrees (Fahrenheit), just an inch or two into the snow pack, that snow is going to be very, very cold.
“So when the rain filters through the snow, it hits (cold area) and can actually get a layer of ice in the middle of the snow.”
In other cases, a glaze of ice on top of the snow can act like asphalt and cause rainwater to run off.
In Grantham, Emergency Management Director David Beckley and Fire Chief Jay Fountain distributed a list of winter safety reminders on the town’s email listserv last week.
The letter reminded residents of the dangers of roof collapses while also pointing out other precautions: residents should make sure vents for heating and hot water appliances are not blocked, use propane safely, and keep addresses visible for emergency responders.
Signs of excess weight on the roof include exterior or interior doors that no longer close easily, cracks that occur in walls, and bowing in timber members or ceilings and walls, according the information sheet.
Beckley recommended that if people are concerned about safely clearing their roofs, they should contact professionals, such as roofing companies.
Beckley said the town tries to send out a seasonal safety reminder. In the summer, for example, residents are reminded about barbecuing safely with propane.
“Quite often, both of us, Jay and myself, have enough experience with the fire department to know what kind of calls we might get depending on (the season),” Beckley said. “A couple years ago (we had a) situation where someone had their roof shoveled off but the snow ended up blocking the vent from the heater.
“It’s somewhat common sense, but they need a reminder,” he added.
Maggie Cassidy can be reached at firstname.lastname@example.org or 603-727-3220.