A Northwoods Almanac for August 9 – 22, 2019 by John Bates
Derechos
A “double derecho” (pronounced "deh-REY-cho") event caused extensive wind damage across most of northern and central Wisconsin during the evening of July 19th and the morning of July 20th. The derecho on 7/19 traveled 490 miles, beginning in east-central Minnesota, traveling through northwest, central and northeast Wisconsin, and finally dissipating in lower Michigan. The second derecho on 7/20 covered 860 miles and spread wind damage from western South Dakota across central and northeastern Wisconsin to northern lower Michigan. In total, the two derechos also produced 14 confirmed tornadoes in Wisconsin.
The most damage occurred across the northern/eastern half of Langlade and western Oconto counties where a “macroburst,” a large downburst of straight-line winds up to 100 mph, damaged just about everything over a path 15 miles wide and 25 miles long. Tens of thousands of trees and power lines were snapped or uprooted across the counties.
Derechos aren’t new to Wisconsin. The largest one on record, at least that I’m aware of, was the July 4th, 1977, derecho which developed over western Minnesota producing frequent winds of 100 mph through northern Wisconsin. The downburst storm crossed eastern Minnesota and north-central Wisconsin, and, within four hours, snapped off tens of thousands of trees in a path 166 miles long and up to 17 miles wide. Broken and uprooted trees littered an estimated 850,000 acres of forest, of which 7 percent (60,000 acres) was virtually leveled.
To place such an extraordinary hand upon the landscape, the 1977 storm had to come from extraordinary circumstances. Temperatures at the top of the enormous thunderstorm anvil clouds dropped to approximately –74°C (-101°F).This extraordinarily cold air fell rapidly toward the earth, warming as it fell, and then spread horizontally along the ground in the direction the storm was moving. As the tempest crossed northern Wisconsin, it generated 25 separate downbursts with the highest winds reaching 150 miles per hour.
In the southeastern part of Sawyer County, the derecho winds hammered the Flambeau River State Forest where winds were estimated to have reached 135 mph. Nearby, the “Big Block,” the largest area of virgin forest left in Wisconsin, was completely destroyed.
In total, the derecho traveled 800 miles in 14 hours from western Minnesota into northern Ohio, and approximately 1,000,000 acres of forest were badly damaged or destroyed
The word "derecho" was coined by Dr. Gustavus Hinrichs, a physics professor at the University of Iowa, in a paper published in 1888. Hinrichs chose this terminology for thunderstorm-induced, straight-line winds because derecho is a Spanish word which can be defined as “direct” or “straight ahead.” Tornado is also a Spanish word, so Hinrichs was matching derecho with its opposite.
A derecho by definition is a family of erratic downburst winds which must be at least 240 miles in length. When warm, humid air rushes into a thunderstorm, colder air falls violently toward the earth's surface, hits the ground, and spreads out horizontally, sending damaging winds across a wide area. Think of it like turning the faucet on full blast in your kitchen sink – when the water hits the bottom of the sink, it splatters horizontally. Same deal for most derechos.
One other massive derecho worth noting also occurred on July 4th, but in 1999. The Boundary Waters-Canadian Derecho was an international derecho that traveled 1,300 miles and lasted 22 hours.The storm manufactured cloud tops up to 65,000 feet high and generated winds in excess of 100 miles per hour, snapping trees in a swath nearly 30 miles long in the Boundary Waters and from 4 to 12 miles wide. One paddler described being in the middle of the storm this way: “I could only see about twenty feet into the soupy air. With the wave tops being blown off the lake and the rain, it was like being in a wind tunnel while being sprayed with a fire hose.”
Over a half-million (585,000) acres of forest suffered damage – an estimated 25 million trees – including one-third (367,000 acres) of the Boundary Waters Canoe Area Wilderness in the Superior National Forest. Many of the nearly 3,000 paddlers in the BWCAW that day faced an entanglement of biblical proportion—how to portage canoes and gear through a baffling snarl of horizontal trees, as much of the forest was tipped 90° onto its side.
August Flowers
Flowering in the fields and along roadsides: goldenrods, black-eyed Susans, sweet clover, wild asters, Queen Anne’s Lace, hawkweeds, fireweed, milkweed, wild bergamot, birds-foot trefoil, butter-and-eggs, chicory, evening primrose, fleabanes, spotted knapweed, mullein, tansy, self-heal.
On the shorelands: turtlehead, jewelweed, Joe-Pye-weed, steeplebush, meadowsweet, swamp milkweed.
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| jewelweed |
In the shallow water: arrowhead, purple bladderwort, smartweed, pickerelweed, bulrushes, cattails, pondweeds, wild rice.
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| beds of smartweed |
Edible berries in fruit: raspberries, elderberries, thimbleberries, elderberry, wild grapes.
Fireweed – The Healer
Fireweed is in flower along most roadsides and open areas, its four-petaled, rose-purple plumes standing tall, and not to be confused with purple loosestrife, which has seven petals. Fireweed may be one of the most abundant plants in the northern hemisphere, growing from 20 to 70 degrees North latitude all around the world.
Flowering begins at the bottom of the spike and proceeds upward, the lower flowers dying and producing three-inch-long curved seed pods. The seedpods split open lengthwise, each one producing 300 to 500 seeds attached to a silky thread that carries the seed on the wind. One study found that 20 to 50 percent of fireweed seeds travel on winds at altitudes higher than 300 feet, and may travel for hundreds of miles. Since an average plant produces 40,000 seeds, that’s an enormous distribution!
The seeds germinate on open disturbed soils, often rising in utter profusion after a fire or an avalanche in the mountains. It’s said to clothe the tundra in the far North and was one of the first colonizers in the heavy ash after Mount St. Helens erupted in 1980. During the WW2 firebomb raids of London in 1940 and 1941, fireweed was seen in “great meadows” in the bomb rubble.
So, it’s a healer, what ecologists call a “pioneer” plant, colonizing sites harmed by humans and nature, and bringing them back to life. The plants may only last a few years following their flush, because they are quickly succeeded by other pioneers like blueberries, bracken ferns, raspberries, and blackberries, which live much longer lives. But the fireweed’s work is to be the first to restart life on bared soil, and for that, we should be grateful.
Migration Already in Motion
Shorebirds have been passing over us and heading south for nearly a month already. Very few stop in our area simply because we don’t have great shorebird habitat like Chequamegon Bay to our north and Horicon Marsh to our south. We also have very few nesting shorebirds in northern Wisconsin, so their departure goes largely unnoticed.
We do, however, very much notice songbirds when they leave, and most of the songbirds that winter in Central and South America will start migrating as early as mid-August. We tend to think of autumn beginning in mid-September, but songbird DNA tells them to get out of town before the first frosts kill most of their food base – insects.
Webworms
Fall webworms are appearing on many shrubs and trees now. These are native caterpillars that form a loose webbing over branches and feed on the leaves. The good news is that fall webworms are more of a cosmetic issue than a truly harmful insect.
If you want to remove them, open up the webbing using a long stick to allow predators, like songbirds, to get at the caterpillars. Or you can use the stick to roll up the webbing and then place the entire web in a container of soapy water for a couple of days. Don’t do what I recently did, which was try to burn them with a torch. I likely did more harm to one of our mountain ash trees than the insects might have done.
Smooth Green Snake and Garter Snake
Mark Westphal, ace photographer near Manitowish Waters, sent me photos of both a garter snake and a smooth green snake. His photo of the garter snake shows the snake displaying its forked tongue, which makes it look rather fierce.
Truth is, however, that a snake uses its tongue to gather scents from the surrounding air, which it transfers to a gland called the “Jacobson’s organ” in the roof of its mouth. This organ then sends the “taste” information to the snake’s brain which interprets what it’s contacting. So, a snake flicking its tongue at you is doing nothing more than determining what kind of critter you are.
Smooth green snakes are relatively uncommon in our area, and eat mainly insects like crickets, grasshoppers, and caterpillars, but also beetles, spiders, centipedes, millipedes, snails, slugs, and sometimes amphibians. They’renon-aggressive and non-venomous, and quite pretty.
They’re also super easy to identify – smooth green snakes are the only snakes in eastern North America that are entirely bright green on their upper surfaces. This camouflages them in their mostly grassy habitats like marshes, meadows, open woods, and along stream edges.
Celestial Events
On 8/9, look for Jupiter about two degrees below the moon. Look for Saturn almost on top of the moon on 8/11 and 8/12. The Perseid meteor shower occurs from 8/8 through 8/13, but it peaks during the night of 8/12 and into the early morning of 8/13. The Perseids average 60 meteors per hour. Unfortunately, the full moon will occur a few days later on 8/15, so the nearly full moon on 8/12 will create a rather bright backdrop.
Update on the Loon-Mallard Adoption
The mallard chick is full grown, and still riding on the backs of its adopted loon parents. See the attached photo kindly shared by Linda Grenzer.
Thought for the Week
Senegalese poet and naturalist Baba Dioum: “In the end, we will protect only what we love. We will love only what we understand. We will understand only what we are taught.”
Please share your outdoor sightings and thoughts: call 715-476-2828, e-mail at manitowish@centurytel.net, snail-mail at 4245N State Highway 47, Mercer, WI, or see my blog at www.manitowishriver.blogspot.com
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