Predicting the weather long-term is never an easy or bulletproof task, no matter the available science and technology. But what about forecasting the health of a lake, based on the weather and environment, months prior?
That’s what scientists continue to do each year for Lake Erie — specifically the western basin — as it relates to summer algal blooms.
Based on two months of spring data collected across the watershed, U.S. scientists suggest mild-to-moderate sized blooms in that area of the lake.
The National Oceanic and Atmospheric Administration (NOAA) predicts a bloom severity range for Lake Erie of two to 4.5 on a scale of one to 10, similar to the last three years.
“Through the spring, conditions have been relatively dry except for a large precipitation and associated river discharge event in early April and another moderate precipitation event in early May,” NOAA said in its spring bulletin.
Ohio’s Maumee River is the main culprit for phosphorus runoff from farms making its way into the lake and causing algae blooms.
Near normal precipitation and river discharge are currently predicted for the remainder of the season (May to July). A more comprehensive seasonal forecast will be issued by NOAA at the end of June.
NOAA oceanographer Richard Stumpf’s office studies satellite imagery of the blooms — once they begin — on a daily basis.
Canadian coastal communities such as Leamington would be most affected from mild-to-moderate algae blooms in the lake, he says, along with parts of Michigan and Ohio.
“[If mild] it’s possible some probably aren’t going to get much on the Ontario coast at all,” Stumpf said. “That’s the good news.”
Why the early forecast?
According to Stumpf, NOAA puts out an early algal bloom forecast for western Lake Erie because there’s enough collected data.
“Quite honestly, we found if we didn’t do it there would be a lot of do-it-yourself forecasts. Like every time it rains, literally … people would say we’re going to have a bloom because it rained.”
“We have enough confidence that we will be in the right neighbourhood.”
The 2014 Toledo water crisis prompted algal bloom bulletins as early as May. The toxic bloom in Lake Erie shut down drinking water access to the Ohio city. The same bloom closed beaches and led to a public health advisory on Pelee Island.
“[In] 2015, there was a lot of scared people about the lake and that’s the first year we actually did this forecast because we realized if we didn’t do it, there would be all kinds of forecasts going around.”
Historically, algae blooms normally ramp up in August into September in the lake.
“[There are] some hints that we might have a long summer.”
After that, when the air cools and the wind picks up the lake temperature drops and the blooms break up.
“They don’t like it windy and they don’t like it cold,” said Stumpf.
Green sawdust effect
For moderate-level blooms, with south-to-southwest winds, green-like sludge can come up the Canadian shoreline along the west side of Lake Erie, according to Stumpf.
“On very calm days, it’s possible you might run into some patches of scum, however, in general, they will be rather localized. There won’t be many of those.”
He says some people, in this scenario, might see little bits of what we call the green sawdust.
“That’s kind of what the algae looks like when there’s a little wind going … that kind of a green sawdust effect, but more likely to look more just a little bit greenish and very unlikely to be up on the Ontario coastline.”
Did the ice cover help?
Stumpf says there’s evidence to suggest winter ice cover has a slight influence on algal blooms.
“There’s a lot of ecological factors and we’ve seen some suggestion that winter temperatures may be a factor in this. We’re looking more closely at that,” he said.
Lake Erie saw 95 per cent ice cover on Feb. 18, according to satellite data from NOAA — a stark contrast from the same time last year when only 36 per cent was iced over. The last time the lake completely froze over was in 1996.
Windsor-based environmental scientist Mike McKay says when there’s no ice cover particulate nutrients in the water in the fall stay suspended and available for the next summer.
“They may be used by algae, for example, and create some of the algae blooms” he told CBC News earlier this year.
Less ice means water temperatures are warmer, says Raj Bejankiwar, a scientist with the International Joint Commission’s Great Lakes regional office.
“The sunlight goes all the way to the sediment and that has a negative impact on the spring and summer blooms,” he previously told CBC News.
“It encourages algae blooms. So lesser cover is not good for the lake in terms of algae blooms.”
Rain matters
How much it rains plays a large role in how big of an algal bloom develops in the shallowest of the Great Lakes.
And until now, there hasn’t been a lot of precipitation in the area, with existing models indicating there might not be a lot on the horizon either.
“The current look is kind of normal rainfall for the next two months and so it would be normal water flow going into the lake. But of course, there’s that uncertainty that you can get something a sequence of events and you get more rain and then it shifts upward,” said Stumpf.
He says their forecasting tightens up as the summer begins — and ends in early July.
“At that point we understand the weather systems really well, whereas right now we understand this year looks better than the last couple of years for uncertainty at this time. That’s the best I can say.”
