We've been having a difficult time with weather this year in the North Country. But let's not write off the floods of spring and summer 2011 as mere freaks of nature. Rather than let these hard-earned lessons go to waste, here are some things to keep in mind for future reference.
This spring, a combination of rains and heavy snowmelt raised the level of Lake Champlain to record levels (>103 feet), inundating the low-lying shorelines. The photos below were taken in June, several weeks after the peak of flooding.
Above: cottage near Rouse's Point (NY).
Below: the high stand stained these cliffs at Split Rock (NY).
When tropical storm Irene struck in late summer, we got more flooding. The total amount of water unleashed was not enough to lift Lake Champlain back up to the spring level (it was at 98-99 feet last week) but it came too fast for local streams and rivers to hold it. The effect was like trying to drink from a firehose, and seemingly benign brooks morphed into destructive torrents.
The owner of this almost-lost home in Keene told me last week that the steep cut-away bluff formed in his yard when the stream smashed the back end of the fire station (left foreground) and ricocheted off the fallen roof to crash against the opposite bank. Now you can barely see the shurnken stream at all amid the cobbles and boulders.
Notice, by the way, that the station is standing fully upright again. Volunteers had it rebuilt in less than a week (see earlier postings for comparison). The fire trucks will be housed here over the winter while folks decide whether - and where - to relocate.
What can we learn from these experiences?
One take-home lesson is that floodplains are called FLOOD-plains for a reason.
Here's a stretch of the Ausable River near Jay, NY (above). Such flats make nice level ground for planting, for roads, for buildings. But they're flat because the river made them so, and the river's work is ongoing.
The short time scales that we normally operate on are often too short to capture the natural variability of the landscapes we live on. "I've never seen anything like this in the 30 years I've lived here" doesn't mean much from the perspective of a river that builds its floodplain in violent fits and starts over many centuries or millennia.
The headwaters of the Ausable look out of place to us when they chew into the bed of Route 73 like this (below). But the river has wandered all over its floodplain in the past, including this very spot, as the newly exposed cobbles attest.
By the way; this critical road has been repaired as of today, thanks largely to pressure from Governor Cuomo (as in "tires will roll soon, or heads will roll").
TAKE-HOME LESSON: These floodplains are likely to flood again in the future.
But how often? Nobody can answer that with precision, but some basic patterns are clear enough to offer some guidance.
Tropical storms like Irene rarely hit this region, and the spring flooding was caused by an unusual mix of rains, spring thaw, and abundant snowpack. Such events are rare, but there are several good reasons to expect what we now call "extreme" precipitation to become more common in the future than it has been in the last century.
Climate models and weather records show that there is a trend embedded in our recent precipitation patterns that would be likely to continue if, as the weight of evidence suggests, it is at least partially due to global warming. If it does continue, then floods are likely to become increasingly common and powerful in this region.
Here's what daily weather records from Dannemora, NY, and Cornwall, VT, tell us about the magnitudes of large local rainfall events during the last century (below).
The blue dots on these charts represent single-day rainfall events between 1908 and 2010 that dropped 2 inches or more of precipitation. Reading from left to right shows that the wettest storms tend to crowd closer to the recent end of the time scale. In other words, our wettest storms have been getting wetter.
These data are available online if you'd like to check them yourself (http://cdiac.ornl.gov/epubs/ndp/ushcn/ushcn_map_interface.html). They're limited to months when rain is more common than snow (April through November) because I was most interested in storms that could trigger immediate floods. I chose Dannemora and Cornwall because their records are longer and more complete than those of most North Country stations, but most of the other sites show a similar pattern.
The differences among these records most likely reflect the patchy nature of rainfall, like that shown on this map of Irene's rainfall from the National Weather Service (below):
The Paul Smiths area only got a 2-3 inch dump from Irene, and Whiteface registered 7.5 inches in 24 hours. But some places were 'way off the scale by comparison, especially in the steep, narrow headwater areas of the Ausable Valley. One person from Upper Jay told me that she measured 9 inches of rain that day, a resident of Keene caught 11 inches in a bucket in his driveway, and another person got 13.5 inches at Johns Brook Lodge. If those measurements are accurate, then it's small wonder that those places suffered the most severe flooding, too.
TAKE-HOME LESSON: Local rainfall and flooding can be more severe than you might expect from the average rainfall of a given storm, thanks to the lay of the land, how fast the rain falls, and how much of it falls on a particular site. So if there's a big storm coming, it's a good idea to pay attention.
Will the last century's wetting trend continue? Personally, I suspect that the answer is more likely "yes" than "no."
Higher temperatures evaporate more moisture from oceans and landscapes into the air, so common sense says that more water should fall when it rains in a warming world. Tropical storms may become more common and more waterlogged under such conditions, and seasonal runoff may increase if heavier rains fall on the typically water-soaked landscapes of spring. This line of reasoning, along with the trend of increasingly extreme rainstorms, suggests that it would be wise to plan for more floods to come even if we don't know exactly when they may happen next.
In addition, climate models that focus specifically on the North Country suggest that our annual precipitation totals are likely to increase by several inches over the course of this century. You can check this out on the Climate Wizard website (http://www.climatewizard.org/), or the report on climate in the Champlain watershed that Mary Thill and I published last year for The Nature Conservancy (http://www.nature.org/idc/groups/webcontent/@web/@vermont/documents/document/prd_002936.pdf).
What can we do about such changes?
General preparedness is always a good place to start. We also experience blizzards, ice storms, landslides, forest fires, and other challenges here, and North Country folks are usually ready for just about anything that the elements throw at us.
This year's floods, however, also showed us which locations are most vulnerable to extreme spring runoff or big storms. Some of those sites came as a surprise - like that little stream channel in Keene - so let's not forget what happened and where. And when we rebuild, let's remember that our roads, bridges and buildings may some day have to withstand a repeat of 2011.
In some cases, an equally valid strategy may be to build things cheaply enough to be replaced easily. When one privately owned bridge in the Keene Valley area was washed out by the spring floods, the owners were able to rebuild it quickly because it was made of sturdy telephone poles. They just fetched the poles from where they had lodged downsteam and laid them back down on the original bridge site.
But more than anything else, the resilience, cohesiveness, and sheer gumption of our local communities will continue to be a major asset for dealing with emergencies.
TAKE-HOME LESSON: North Country folks can really pull together when things get tough.
You can see plenty of evidence of this throughout these blog posts, and here's a bit more. Last Saturday, the tiny settlement of Whallonsburg put on a spaghetti dinner and dance at the Grange to raise money for neighbors who lost their homes when the Boquet River flooded (below).
Keene already looked much better by last week, thanks to massive efforts by the entire community, Cuomo's "Labor for your Neighbor" initiative, and generous support from people outside the area (below).
And here's a final take-home message from Keene (below).
Remember, just because it's not on national TV now doesn't mean that this story is over yet. Far from it; lots of people still need help. Here are 3 suggestions for ways you can get involved:
1. Henrietta Jordan posted this comment on behalf of Keene: "The community will need lots of help recovering from the storm and rebuilding businesses and homes ravaged by flooding Please send your tax-deductible contributions to Keene Flood Recovery Fund, c/o Adirondack Community Fund, PO Box 288, Lake Placid, NY 12946. (Checks should be made payable to ACT/ Keene Flood Recovery Fund.)"
2. North Country Public Radio's site with suggestions for ways to help: http://www.northcountrypublicradio.org/hurricaneirene.html
3. Labor for Your Neighbor: http://www.governor.ny.gov/laborforyourneighbor