Now that the weather has finally warmed up, we can appreciate ice a little more. Among other things, ice greatly improves summertime drinks, and an icy watermelon is hands-down better than a warm one. And in this part of the world, ice also provides us with unique wildflower meadows. Along stretches of riverbank in the southern Adirondacks, rare Arctic-type flowers are blooming now in the fragile slices of native grasslands that are meticulously groomed each year by the scouring action of ice and melt-water.
Known as ice meadows, these habitats are few and far between in the world. They are found almost exclusively near the headwaters of rivers which originate in mountainous terrain; in New York State this includes the St. Regis, Sacandaga, and Hudson Rivers. In these habitats, ice mounds up along the banks to depths of between three and five meters each winter. Obviously, such quantities of ice tend to compress the plant community on the shoreline, but the mini-glaciers also take a long time to melt, leading to a truncated season with unusually cold soils for ice-meadow inhabitants.
For these reasons, as well as the fact that inundation will kill the roots of most tree species within about ten days, native trees cannot develop in ice meadows. The groundcover species which do survive and thrive there are adapted to extreme short seasons. According to the SUNY College of Environmental Sciences and Forestry’s New York Natural Heritage Program, thirteen rare plants are found on New York’s ice meadows, though not all occur at every site.
Dwarf cherry (Prunus pumila var. depressa), New England violet (Viola novae-angliae), auricled twayblade (Neottia auriculata), and spurred gentian (Halenia deflexa) are among the plants a visitor is apt to see. Personally, I’d like a glimpse of something called the many-headed sedge (Carex sychnocephala), but only if accompanied by a team of martial-arts experts. In addition to these boreal plants, other native wildflowers like tall cinquefoil (Drymocallis arguta), bastard toadflax (Comandra umbellata), and thimbleweed (Anemone virginiana) often add to the profusion of summer blooms in an ice meadow.
The processes which account for the formation of ice meadows are not completely understood. It was often thought that mini-vortices of slushy ice called frazil ice were responsible for scouring the riverbanks, but the deposition of frazil ice is not particularly violent or forceful. And since frazil ice is known to form in just about any river or good-size stream in NYS, it is only part of the story. The shape of the riverbed and the size and nature of the watershed probably have a lot to do with ice-meadow genesis.
North Creek resident and lifelong naturalist Evelyn Greene has spent countless hours observing ice meadows, especially during winter. She suggested to me that the scouring action of water, a force which after all has carved gorges such as the Grand Canyon, is responsible for the ice meadows at least as much as the ice. She points out that being under flowing water for more than a month per year leaches out nearly all available nitrogen from ice-meadow soils. Since the plant community is one which is common to the thin, nutrient-poor, acidic soils at high elevations, I would call that a confirmation. Greene also notes that ice-out conditions have changed in recent decades, with multiple significant thaws during winter becoming common.
A good example of an Adirondack Park ice meadow can be accessed through Warren County’s Hudson River Recreation Area on the Golf Course Road, about 1.4 miles (2.25 km) north of NYSDEC’s Region 5 Warrensburg Suboffice. From the Recreation Area parking lot you can hike out to the ice meadows in a few minutes. The New York Natural Heritage Program lists “trampling by visitors” as a threat to ice meadows, so please stay on marked trails, and when on the shoreline, do not step on any vegetation. Other ice meadows can be found in the Silver Lake Wilderness and Hudson Gorge Primitive Areas in Hamilton County.
In a region characterized by long winters, it can be refreshing to enjoy mountains of ice, or at least the results thereof, in short sleeves.