Showing posts with label precipitation. Show all posts
Showing posts with label precipitation. Show all posts

Wednesday, September 08, 2021

Hurricane Damages DR Canal Towpath--Again

Driving into Princeton the morning after Hurricane Ida swept through, my first thought was to check Princeton High School. Had the school flooded yet again, ruining the performing arts stage for a third time? Fortunately not, judging from appearances as I peered in the windows. 

My next thought was the towpath along the DR Canal. Ten years ago, almost to the day, Hurricane Irene rendered the popular towpath almost unusable for walking, jogging, and biking, eroding it in places, coating its cinder surface with mud in others. Full repair, probably with FEMA money, was not completed until 2019--eight years later.

This is what I found after Hurricane Ida. A combination of fallen trees and thick mud have rendered sections of the towpath impassible, only two years after it was resurfaced.

Here's a closeup of the flood's deposits of silt that walkers and bikers encountered.
While some areas were covered in mud, others were scoured, stripped of the cinder surface that made for a comfortable walk.

At Rogers Refuge, the hidden floodplain preserve upstream of Carnegie Lake, a plaque marking the high water mark ten years ago was exceeded by an inch by Hurricane Ida. 

Elsewhere in Princeton, Mountain Lakes reportedly sustained damage to its bridges. In Herrontown Woods, the trails remained in good condition, but the power of the rain and runoff was evident in the widespread scouring of ground and the flattened vegetation. 

As our machines pour more CO2 into the air, the warmed atmosphere can hold more water, leading to rains that are extraordinary in their density and weight. The raising of CO2 levels by 50% represents a militarization of the atmosphere, where clouds can now carry tremendously heavy payloads of water. 

The need to build and maintain more and better waterbars to divert runoff from trails--a local form of "climate resilience"--is only adding to the workload faced by the largely volunteer organizations that care for Princeton's open space. More than a decade ago, working on habitat restoration at Mountain Lakes, I began thinking of climate change as a dark cloud on the horizon threatening to cast a shadow over our work in local preserves. The incredibly heavy rains are one example of how what once was foreboding has become a reality. 

Of course, one reason so little is being done about climate change is that the episodes of extreme weather quickly pass, segueing often into pleasant weather. Hurricane Ida seemed to sweep away the hot, humid summer, leaving in its wake refreshingly cool air. 

This hurricane's most lasting legacy may be a change in our relationship to water, perhaps the beginning of a retreat from the shorelines we so dearly love. The plight and uncertain future of the towpath--that wonderful waterfront trail--is only the most dramatic example of how a climate of our own collective making is beginning to threaten that which we hold dear. 

Tuesday, February 02, 2021

A Rather Long Snow Storm

Here in Princeton, we have artisanal snow removal services, as in this thoughtfully crafted mohawk for the Prius.
Good news about the frontyard raingarden: it works great as a snow garden as well.

During this extended, ground-breaking, or at least ground-exposing, Snow Removal Initiative (SNI), it was important to take frequent breaks to document the innovative "shoveling" technique being used. The Royal We Committee believes this approach, if successful, could serve as a model for other homeowners to emulate. Later in the morning, we saw neighbors beginning to utilize this very method, suggesting our demonstration project could have a transformative impact on snow removal in Princeton and beyond. 

The Initiative included a research component. Careful study of this cross-section of the cliff face reveals the various strata laid down by the storm. This having been an unusually long snowstorm, it's understandable that the darker patch in the middle was at first mistakenly dated back to the early Devonian. Further analysis and some equipment tweaking showed that snow in the darker stratum likely fell during the warmer daylight hours the day before, with the lighter layers above and below having been deposited during the preceding and following nights.

Other keen observations: some of the neighbors didn't get the memo. Recycling postponed until Saturday, or the mid-Anthropocene, depending on how long the storm lasts.

What is snow good for? Enforced social distancing, for one. Not likely to have a close encounter with the neighbor for some time to come. And the kids can sort of remember what it used to feel like to get a snow day.

Other writings on excessive snow include an oldie but goodie: Snowbound Language

Thursday, February 09, 2017

Graupel--A Special Form of Snow

All snow is special. Like children, except more numerous and lower maintenance, no two snowflakes are the same. As we know, snow that falls in Princeton's coveted 08540 zip code is extra special, and on the last day of January, there fell a particularly special kind of Principitation. Instead of flakes, the snow looked more like small beads of styrofoam.

When it fell one day two years ago, thinking it needed a name, I coined what seemed like a new term: snubbins. A recent google search, however, revealed that the word "snubbins" is sometimes used to refer to medium sized breasts. Who knew?

A less conflicted name came out of the blue during a trip to the Whole Earth Center, when longtime employee Bill excitedly showed me a printout from Wikipedia, describing this special snow as "graupel". To quote: "Graupel, also called soft hail or snow pellets, is precipitation that forms when supercooled droplets of water are collected and freeze on falling snowflakes, forming 2–5 mm balls of rime." These supercooled droplets, suspended high in the air and still liquid down to -40 F, collect and freeze around the snowflakes as they fall towards earth. The behavior of supercooled water came up in another recent post admiring the patterns the minipond water makes when it freezes.

In this photo of the graupel collected on our backyard fillable/spillable minipond, or mini-rink this time of year, you can see their shape. In the middle of the photo there's a snowflake still visible, only partly covered in rime.

In this photo, some of the graupel takes the shape of corn kernels.

Favorites from the archive:

Principitation: Coins and defines useful terms for various kinds of snow and snowy objects, e.g. snirt, snoodle, kerfluffle, and we-cicles (plural of i-cycles).

Snowbound Language: A Victor Borgesque story about what happens when snow blankets the english language.

Sunday, January 22, 2017

Water: Our Backyard Artist in Residence

Even in the winter, or maybe especially in the winter, there's a lot of creativity and beauty in our backyard, thanks to a fillable-spillable 35 gallon black tub that catches runoff from the roof. If the night dips below freezing, the open water becomes a canvas for elaborate 3-dimensional designs.

Why the water doesn't freeze flat is hard to fathom. Sometimes, if the night's freeze has been light, these geometric shapes will frame miniature pools of open water that jiggle when the tub is tapped.

Cold brings out an unexpected beauty in water, and sometimes in ourselves, if we have clothes to match the weather, and take the cold as a bracing stimulant rather than, as Garrison Keillor would say, "nature's attempt to kill us."

These images were first posted at as News Flash: Nature is a Geometer, in a post that links to an Exploratorium exhibit that shows how supercooled water can freeze over in a flash.

Saturday, December 31, 2016

Winter Has Been Downsized

Like the incredible shrinking chocolates that cost the same but come in smaller packages, winter isn't exactly filling its three month package like it used to. This Snow Wall-E was looking pretty lonely on Hawthorn, before it too succumbed to the browns and grays of mild weather.