As a blanket of snow begins to melt off in much of the country this week, superintendents are left wondering just what they are going to find underneath.In some parts of the country, that snow layer has served like a warm, cozy blanket since December. For others, it masks a layer of ice that might be benign, or one that could spell disaster.
Jim Bluck, CGCS at Forest Dunes Golf Club in Roscommon, Mich., says he is expecting to find some of the healthiest turf he's seen in years whenever the snow melts at the course in north-central part of Michigan's mitten. The reason, he says, is timing.
"It got cold fast and the ground just froze. Then, the snow came. It's been like an insulating blanket for the turf," Bluck said.
Located about 100 miles south of Mackinac Island, Forest Dunes typically receives upwards of 150 inches of snow per year and remains covered from early December until early April. The Roscommon area has received about 140 inches of snow so far this winter, Bluck said.
When dry ground freezes rapidly, a lack of moisture in the plant means the snow can help protect the dormant, but otherwise healthy turf, throughout the winter, said Nathaniel Mitkowski, Ph.D., at the University of Rhode Island.
"If there is no ice in the snow pack, particularly at the soil interface, you can leave the snow on the green all winter," Mitkowski said.
Even when overnight temperatures in Roscommon dipped to as low as minus-16 degrees on four occasions in January, and with accompanying wind-chill factors in excess of minus-30, that snow blanket kept the surface temperatures at manageable levels, Bluck said.
"It was 20 degrees at the surface, because we had so much snow," he said. "The cold hasn't gotten to the turf. The wind hasn't gotten to the turf. I expect my turf to come out just fine."
Just to south, however, the news isn't so good.
Snowfall amounts in southern Michigan and other parts of the Midwest are way above normal. But those snow events have been accompanied by freeze-thaw cycles and, in some parts of Ohio, freezing rain followed by snow on at least three occasions.
About 65 inches of snow has fallen since Dec. 1 in the Detroit area, including a record 39 inches in January. The norm through mid-February is 27 inches, according to the National Weather Service.
Ice layers underneath the snow have sent some superintendents out with aerifiers equipped with solid tines to break up the ice, or bags of heat-hugging black sand or Milorganite to expedite the melting Process. Some even are taking blowers to greens to dry the moisture prior to the next freeze cycle.
Others, like Dan Koops at Findlay Country Club in northwestern Ohio, have become innovators at protecting turf from winter conditions.
To date, 63 inches of snow have fallen in northwestern Ohio, and the 42 inches that fell in January was a record, according to the National Weather Service. Like the Detroit area 90 miles to the north, Findlay also was hit hard by sub-zero temperatures, heavy snow and strong winds in early January. When the wind blew snow from the greens, Koops and his crew removed some from the bunkers and anywhere else they could find it and piled it on FCC's annual bluegrass putting surfaces that the superintendent says haven't been renovated since architect Thomas Bendelow built the place 106 years ago.
With temperatures the third week of February expected to climb into the 50s for a day or two, some of the snow and ice is expected to melt off. The question is, what will happen to saturated turf when overnight temperatures dip below 20 degrees by the weekend and into single digits again within a week in areas where snow cover this winter is measured in feet rather than inches.
"The problem arises when you get freezing and thawing cycles and/or rain," Mitkowski said. "When this happens, water percolates to the bottom of the snow pack and inevitably freezes back into ice.
"My guess is that if the snow melted today and the ice went with it, the grass would probably be fine. But if the temperatures get severe afterwards and more snow/ice/freeze/thaw happens, you could still be looking at damage."
At Findlay, ice has been on the course for about 35 days, Koops said. He's unsure of what to expect when the snow melts this week. He is more concerned about damage from the flood-prone Blanchard River that winds through the course. Entering his third season at the club, Koops avoided any flooding events in 2012, but the river ran up on parts of the course three times in 2013. As voluminous amounts of snow begin to melt away, the first event of 2014 is almost a certainty.
Opinions vary on how long Poa can survive under ice, but Michigan State turfgrass pathologist Joe Vargas, Ph.D., says the range typically is 45-90 days before turf death can occur due to toxic gas exchange. Bentgrass, he says, can survive for up to 120 days.
If the ground is frozen when an ice layer is formed, there is less chance for an exchange of turf-killing toxic gasses, Vargas says. The warmer the soil, the faster oxygen escapes the turf, increasing the chances for the exchange of toxic gasses and turf death.
In December thaw cycles, Koops has used squeegees to remove water from Findlay's greens. In January, there often was too much snow, and above-freezing temperatures lasted for a day or less.
"If the Poa annua breaks dormancy and takes up water swelling the crown and the ice melts and refreezes that night wherever there was standing water it will die," Vargas said. "Creeping bentgrass does not break dormancy for a long period of time and is not affected by the reformation of the ice. It is going to be interesting to see what happens with the late winter."
Of major importance, Koops said, is maintaining an open line of communication with the membership.
"I have been warning them that we probably will have some pockets of dead turf in those areas where water settles and ice has been standing," he said. "I haven't seen any spots that are brown. I would like to get a full meltdown and see what's out there. This is one of those winters where you don't know what you're getting out of it. And there isn't anything you can do about it."