PA: Holtwood Oldfields and Coventina Rising

On this Sunday's walk with Bug the coonhound, we wandered the River Hills on the Lancaster County side of the Susquehanna. It was a short few miles to stretch our legs. This area has been heavily altered over the past two centuries. It isn't hard to go a mile in any direction and find spoils heaps from dredging behind the Holtwood Dam, power line right-of-ways cut brutally through the forest, borrow pits, and all sorts of water engineering from the dam itself to reservoirs and mill races. Now we are contending with new buried pipelines and expansions of natural gas pressure stations, a new natural gas plant, and local protests. In winter this area can look much more brutalized and isn't exactly a wilderness escape, but it can often yield surprising things. The temperature today was a balmy 48' F when we started out and when we finished (at a trot) it had dropped to a chilly 32'F in just an hour at mid-day.

Fog rolls over the hill - brrr!

The clues for this drop in air temperature hung over the river as we crested a hill along a stretch of trail that ramble through an oldfields section of the Holtwood Preserve.  A slight warm breeze earlier in the walk should have tipped me off, but coming over that hill, I was awestruck and not in a very scientific frame of mind, as a dark wall of river fog rolled up from the valley. Within minutes I was shivering in the cold winter fog as the light faded to dusk. Even the barred owls were fooled into hollering in the low light. This is the stuff of spooky stories, I thought, not very Christmassy!

Milkweed pod husks

I'd been snapping pictures of some of winter's bleakness - skeletal remains of a deer, crackling dry milkweed pod husks, patches of snow that remain from our December snow squalls - the kinds of vistas and visuals that would have interested Jamie Wyeth - so I was in that kind of mental space. I looked up from my snaps to see an Amish family with their English friends moving quickly through the field, having come up from the river. We exchanged our greetings and Amish Dad said "Getting really cold really fast down there! The woods should be warmer!"

Wyeth-looking snow patches

As I looked beyond them I could see the wall of fog rolling towards us. They drew their jackets and blankets tighter and hurried into the woods. I just sort of stood there staring. As the fog shrouded the oldfields, the temperature plummeted and dew formed on my binoculars, camera, even on Bug's black coat! Brrr! I immediately thought of the fog-rise of Celtic goddess Conventina, the keeper of watersheds and rivers, who - according to Roman mythologies I encountered while hiking Hadrian's Wall - would make her energy and power keenly felt in sudden, disorienting marine fogs and unexpected squalls. As the fog thickened, even Bug, ever onward the intrepid tracker hound, wanted to go back and follow the Amish family into the woods.

Skeletal remains of Common Mullein

Of course (she says confidently) I knew what was really going on. The great lake behind the dam at Holtwood had undergone its seasonal conversion. Warm and cold water layers had flipped, exposing the warmish air to cold water surface temperatures. The warm breeze I'd felt earlier, swooping in to the river valley was cooled to its dew point and a great cloud of fog had formed.  The lake inversion fog, called marine fogs along the coast, can be fast-forming and fast-moving. Within minutes the great cloud had enveloped the entire river hill and just as quickly, it rose and hovered a hundred feet over the valley, blocking the sun and locking in the the chill. It was cold! We didn't turn around but jogged into the wooded valley, towards the river. We kept jogging till we reached the old Holtwood Road, slipping and sliding down a steep bit of trail.

Mullein spike laid low

Jogging uphill to the Holtwood Arboretum certainly helped warm me up while Bug found a whole new class of roadside smells to stop and decipher. Scent-filled embankment slides of whitetailed deer, a squashed pile of horse poo, and the remains of a squirrel thrilled her coonhound nose. The few houses we passed were busy stoking fresh fires as pellet stoves and wood stoves scented the air with wood smoke.  We met up with the Amish family coming the other way. We stopped and chatted a bit, all of us a little warmer for our efforts to move faster. "Seems to me this is late for the river fog," said the elder woman, "These fogs usually start in late October and early November when the pond flips. But times are changing." Yes, they are, I agreed.

"English" and Amish families bundle up and move fast into the woods.

Amish farm women are great diarists and have for generations kept detailed records of seasonal changes. If anyone is looking for a great climate change history  project, as I mentioned in a recent NOAA workshop for climate data visualization, you can't beat farmers journals. I've seen an Amish woman's journal that goes back six generations and have often wondered if they might let me photocopy it. I'd need to find a translator, however, as it's in German.

Bug on a scent between fields

Our fast hike ended back at the car within the hour that we started. The inversion fog had lifted but the cold was bone deep. I blasted the heat in the car for ole' Bug who sat shivering. We stopped at the local chicken place to get her Sunday tenders treat and while standing in line to pay, a welder at the new gas plant - another sore spot in our much-abused energy landscape - remarked that the cold fog had come on so suddenly at the plant that they had to stop work for a few minutes until they could see. "It was downright spooky!" he said.  Coventina, the Goddess of Watersheds pulled a fast one today!

Cold fog lifting, there's new ice on the river.

Notes:

Coventina can be found in museum collections along Hadrian's Wall. I found her in Carlisle and Wallsend. For some reason, she's associated with witchcraft, but I think she represents a beautiful Druid mythology that got mixed up rather unfairly in Roman and Christian assimilations. As the goddess of watersheds, she has a very scientific sensibility to me. On our summer's Hadrian's Wall hike we crossed the oldfields containing the standing stone that marks Coventina's Well near Carrawburgh.  See Wikipeadia https://en.wikipedia.org/wiki/Coventina