Ranger Kathryn's Arches

July 10, 2013

Collision course with an anvil

Filed under: Uncategorized — Kathryn Colestock-Burke @ 6:03 pm
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A towering cumulonimbus cloud denotes atmospheric instability in western Nebraska.

A towering cumulonimbus cloud denotes atmospheric instability in western Nebraska.

You can see it coming for a hundred miles or so out there in Nebraska, freeway bearing northeast and quickly-mushrooming anvil cloud bearing southeast, aiming to meet in another hour right where you have a motel reservation. It’s hard to imagine anything could sneak up on anyone on the plains, where you can see forever because the corn doesn’t obstruct a single sight line. No surprises. Just enormous storm clouds that seem to stalk you, perhaps menacingly, but that’s anthropomorphizing, as anyone can tell you that storms just barrel in without stalking.

Bright, they are. Cumulonimbus (Cb) cloud tops are full of ice crystals reflecting the brilliant sunlight, tricking you into thinking it is a Safe Thing when its Latin derivation suggests otherwise: cumulus “heap,” nimbus “storm/rain.” One look at these monstrous upwellings of air and water vapor and you sense that its unsettled nature will likely bring precipitation.

Dangly clouds are not my favorite.

Dangly clouds are not my favorite.

Just to the north, the lowest layers seemed to be dragging heavily from the cloud bottom. Seeing no rotation, I didn’t get the sense of a tornado; it was nonetheless disconcerting. The cloud was dangling. Dangling clouds, to midwesterners, are often unsafe. These photos taken at 70 mph with my iPhone don’t do justice to the mysterious nature of  the pannus variety of cumulonimbus, but at least now Wiki has given me a name for it:

Fractus clouds (scuds) are small, ragged cloud fragments that are usually found under an ambient cloud base. They form or have broken off from a larger cloud, and are generally sheared by strong winds , giving them a jagged, shredded appearance. Fractus have irregular patterns, appearing much like torn pieces of cotton candy. They change constantly, often forming and dissipating rapidly. They do not have clearly defined bases.

Sunset illuminates a cloud-shred.

Sunset illuminates a cloud-shred.

Thirty minutes later, this towering giant was so electrically charged that I counted 28 flashes of strobe-like lightning in 60 seconds. It felt alive, some sci-fi monster rumbling in its innards, ions and updrafts and unstable air converging on North Platte just outside my motel room. I stood alone at the  west-facing window and trembled involuntarily, several hundred megawatts of electrical power staring me in the face; until it weakened, there would be no sleep.

January 31, 2012

Entrusted with weather data collection

Filed under: Uncategorized — Kathryn Colestock-Burke @ 7:32 pm
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Part of our humble weather station at Island in the Sky District

Every morning as I reach work, I peek into the eight-inch canister behind the visitor center. If any precipitation has fallen in the preceding 24 hours, it is measured exactly. Multiple measurements are taken in winter: new snow depth (measured on a white board swept clean daily), standing depth (measured on a stick secured in the ground), and new snow in the canister melted and measured to the nearest hundredth of an inch. Our digital temperature recording device marks highs and lows of the previous day. We note the hours during which weather events happened, any related observations (e.g., “snow squall with thunder clap,” or “wind blew tents down”), and oddities like hail or fog. Part of our morning procedures includes logging on to the National Weather Service data collection site and putting all our numbers safely into their system. I hope that gives meteorologists something interesting to study when storms are utterly absent.

This post was unnervingly monochromatic, requiring the addition of a recent sunset photo from my front door.

I must say that my favorite hand-written observation in the weather book last year was on October 25: “screaming double rainbow 4:37 pm.” Take that, National Weather Service!

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