Roseway Gusts

Posting these here to explain (1) why we have such rocky soil and high radon; and (2) why it's so windy here (compared to more south & east parts of PDX); especially for those of us closer to Sacramento St!

Rocky Butte was a volcano that erupted basaltic andesite about 1/4 million years ago. It is now heavily eroded and has shrunk over time. (Prune Hill - the big hill in Camas - was an even bigger one).

Around 15,000 years ago at the end of the last ice age, glaciers up north melted and flooded the Columbia River a bunch of times. (Picture 1 is a missoula floods inundation map.) This whole area was under water and Government Island was a tiny lump in the bottom of the river.

As the water headed west past big hills like Prune Hill and Rocky Butte - the river was narrow and moving fast, keeping rocks and debris moving.

After passing these Prune Hill and Rocky Butte - the water slowed and spread out. Now a bunch of rock washed up at the edge of the huge flood river since the river wasn't keeping it rolling. The Missoula floods went on a while. The piles got big. ("Pendant bars.")

This made Mill Plain and the Alameda Ridge. They're gradual and not obvious at the river side were they were washed up at over time; but have big drop offs at the far side of the river's reach (Burnt Creek in Vancouver, bottom of the ridge over here). Our houses are on a giant pile of radon-filled rocks from Canada!

Now when cold air comes from up north down the Columbia, the Gorge makes a nice little wind tunnel. The farther north and east you are (Troutdale, Fairview, north and east of 205) the worse it is. In the case of Roseway, we're both north and east, on the top of the ridge which is exposed to the wind. (My friend lives in one of those tiny houses up on the hill on Morris between 68th and 70th; I don't have anything to prove it but I always feel like those houses are the very highest part of the ridge around here.)

AND, east wind blows over and around the Butte, creating turbulent air on this side of it. Instead of just surface wind coming straight east across an exposed plain, we're getting surface wind AND slightly higher wind, condensed over the top and around the sides of of the butte and swirling around here on the "lee" side. Picture 2 shows this wind effect.