Saturday, January 26, 2008

The Sidewalk is Deadly

So, it's raining. Plain old Oregon rain, cold, but not a big deal -- except the temperature at ground -level is currently 28 degrees F., which makes for a nasty condition sometimes called a "silver freeze." (When it gets worse, they tend to call it an "ice storm." I'd never heard of such things growing up in Louisiana. First winter we were up in Oregon, we had one. Didn't look like much to me, so when I went out for my daily run of a couple miles, I stepped onto my driveway and promptly slid all the way to the street corner on my ass. At that moment, I decided to take up lap-swimming at the nice heated indoor pool instead of jogging ...)

If the condition gets bad enough, you just stay home. Snow-chains don't help, studded-tires, Yak-tracks on your shoes, nothing.

Unlike seeing great icicles hanging from the eaves as a warning, the first stages of this are deceptive. With the silver freeze comes black ice, a term that would be better called invisible ice. The sidewalks, being concrete with a higher albedo than asphalt, tend to ice over first, whereas the roads absorb more heat, such that it is. (Albedo is why a black car is hotter in the sun than a white one, though even dark material can reflect quite a bit of light. I have it that the surface of the moon has the same albedo as asphalt. Pretty impressive.)

Come the freezing rain, you step out onto the sidewalk, it looks fine, but of a moment, you find yourself skateless on an ice rink. Even so, you can keep your balance on the flats. But, if you come to a rise? Ice-skating uphill is a bitch.

When walking the dogs, better to keep to the ground. It gets crunchy, but unless the condition persists for a while, the thin layer of ice breaks as you walk upon it, and footing is more secure.

Which is to say, if you are in or around Portland, OR, today, and you need to go out, tread with care. The hip you save may be your own.


Tiel Aisha Ansari said...

Urgh! Well, at least the dogs aren't too badly off; they don't have far to fall. Unlike you :)

It's well above freezing at our house; puddles that haven't been liquid in a week are starting to melt.

Steve Perry said...

Normally, I keep them leashed and we go for a mile or so; however, the park behind the drugstore was empty this morning -- big surprise in the freezing rain -- so I let them chase the crows and squirrels for a while. In lieu of a longer hike on the treacherous walks, ten minutes of full-out running squirrel-pursuit works wonders for burning off that cooped-up-in-the-house energy.

envaneo said...

Worst kind of weather is freezing rain. I can take the -25C weather, even the wind chill but freezing rain is the worst.

I posted a couple of pictures on my blog taken at 2:20pm Sunday afternoon Edmonton time. It was -22C out there the time these pictures were taken.

Freezing rain is the worst kind of weather imaginable because it's so unpredictable

Jim Shannon

Jim Shannon

Kai Jones said...

Explaining black ice to new people is really hard. Yes, the road looks dry, it's not shiny--but notice that it's black instead of grey. It's iced over and slick.

Steve Perry said...

Our ice melted off, but we got a dusting of snow last night -- maybe an inch on the ground at my house. Roads are clear in Portland, according to the news.

Supposed to turn to rain later today.

Where I grew up, it snowed maybe once every ten or twelve years, and usually just a dusting. City shut down, and every went out to make snowmen.

It was weird -- whatever fell would get rolled up so you'd see giant snowballs sitting in the middle of bare, St. Augustine-grass lawns ...

Steve Perry said...

Well, turned out the dusting was enough to bollix the roads -- my wife couldn't get out of the neighborhood, 4WD nothwithstanding, the roads are still icy ...