Landscape reveals signs of 12,000 year old flood
By Tom French
If not for the word, “glacial,” one might confuse this headline for any number of events in the Adirondacks over the last two decades and not the wall of water that tore across Clinton County 12,000 years ago.
For most of the last 75,000 years, Adirondack history has involved mile-high ice with cycles of advancement and retreat. During the last melt, before whales were swimming over the foothills, a flood of biblical proportions ripped across the northern Adirondacks. Signs and vestiges of that flood, along with rare ecological niches of jack pines and otherworldly landscapes can be found at the Adirondack Nature Conservancy’s Gadway Sandstone Pavement Barrens, the DEC’s Gulf Unique Area, and Flat Rock State Forest.
Glacial Lake Iroquois, Lake Ontario’s precursor, was blocked by an ice sheet close to the current location of the Thousand Islands. Generally, the lake drained to the southeast near Rome and eventually through the Mohawk River Valley to the Hudson. But as the ice sheet continued to melt, the lake expanded over the St Lawrence Valley as far east as the Ellenburg area. At some point, a breach occurred along the edge of the ice in the area of Covey Hill near the Canadian border. Over the course of a few months, enough water to fill a third of Lake Ontario rushed out and scoured the surface.
Perhaps the most dramatic and unusual remnant of this catastrophic event is at the Nature Conservancy property – a 520-acre preserve with one of the largest jack pine barrens in the eastern United States near the southern limit of its natural range. You will not feel as if you’re in the North Country and it reminded me of the desert southwest because of the stunted trees, thin soil, and drought-prone environment.
The preserve is open summers through early fall. Visitors are asked to remain on the trails in order to prevent erosion and preserve the fragile vegetation. Beware – the exposed sandstone can heat up to over 100 degrees Fahrenheit in the summer.
Access is from the Cannon Corners Road, 2.5 miles north of Route 11. A blue and white Nature Conservancy sign identifies the entrance on the left. After a third of a mile along a narrow gravel road through a mature and active sugarbush, the landscape changes dramatically as you drive up onto the sandstone bedrock. A parking area is on the left. Visitors can hike a 1.1-mile trail and explore the “pavement” further along a snowmobile right of way. Look for ripples in the exposed rocks – signs of an ancient (500-million-year-old) shallow beach frozen in time.
Head for the border
Upon returning to the Cannon Corners Road, head north 1.7 miles to the DeCoste Road and then 1.5 miles to the DEC Gulf Unique Area – a deep chasm, literally crossing the international border, carved out by the cataclysmic flooding.
Visitors have two options from the parking area. The easier is the MAPPWD (Motorized Access Program for People with Disabilities) trail – a right-of-way across private property. Simply follow the road until its junction with the red trail in a little less than a mile.
The other option is the red trail that begins in the northeast corner of the parking area. It meanders through a forest of mostly white pines and rolls over several ledges before bordering a wetland with active beavers and crossing the first bridge. Shortly later, the character of the forest abruptly changes to hardwoods – beech, maple, ash, black and pin cherry. When I last visited, it was spring, so the scene through the forest was bright and forever. We heard, then spotted, a hairy woodpecker attempting to attract a mate. Many trees showed signs of pileated woodpeckers as well. On previous trips, pink lady’s slippers were abundant.
After crossing Allen Brook (turn left after the bridge), the trail crosses a cobblestone hill where rocks, picked up from the flood, fell out of suspension and were pushed to the side of the escaping water. The trail is rough and reminiscent of many high peak trails. At 1.5 miles from the parking lot, it connects to the MAPPWD trail, a clearly marked intersection. Turn right for 500 yards then right again at another intersection. The MAPPWD trail continues straight for another eighth of a mile before terminating at a rock wall and fence. Unfortunately, the Gulf and border area is not accessible for people who require a wheelchair.
The red trail crosses another cobblestone area before reaching an old woods road into the Gulf Area. Glimpses of the Gulf open to your right with herd paths along the top of chasm. I encourage you to explore as there are ledges with open vistas across the Gulf.
We happened upon a thick rope tied from tree-to-tree descending to the bottom. We took advantage of the assist and explored the base of the gorge and a 60-foot waterfall with sedimentary strata covered in bright green moss wet from splash and spray.
After about three miles, the trail ends at the US/Canadian border with marker no. 688. Views to the east reveal more of the chasm. Another marker can be seen on the opposite side of the Gulf and in the distance to the west.
We returned to the car via the yellow and MAPPWD trail. Follow the woods road from the Gulf to a clearly marked (and posted) property line. The yellow trail is to the left over the cobblestone. It was poorly marked and sometimes hard to follow. The DEC website also mentions a hermit’s cabin. Eventually, you reach the MAPPWD trail. Turn left and go straight. Ignore any intersections with other trails clearly used for ATVs by the private property owners. Signs at the property lines are confusing – just go straight to return to your car via the MAPPWD trail.
Altona Flat Rock
Another area impacted by the glacial flooding with a jack pine population is the Altona Flat Rock Sandstone Pavement accessible along Rock Road parallel to the Military Turnpike (Route 190) between Plattsburgh and Ellenburg. At times, the road is the exposed bedrock. High-clearance vehicles are recommended. The DEC manages several parcels of the Flat Rock State Forest in the area. Recreational possibilities include biking or hiking along 1.4 miles of forest haul roads and two miles of snowmobile trails.
More than 500 acres of the Flat Rock Forest, including areas of jack pines, burned in 2018. Contained and extinguished by nearly 200 firefighters from several departments over five days, the burn area has now become an area of scientific research as the forest rejuvenates in the wake of the fire. Fire is crucial for the long-term survival of the jack pine forest ecology because their cones need fire to open and release seeds. Indeed, lack of fire can reduce the health of the tree stand and lead to local extinction.
Discussions among various stakeholders in the area for prescribed burns or other treatments are ongoing.