Portland: Tephra Hazards? (St. Helens, Adams: gated, farmers, area)

[Samoi137]

Anyone in the Portland area ever have problems with tephra, perhaps during small explosions? USGS Web site says "minor amounts of tephra can make breathing difficult for those with respiratory problems, the elderly, and infants. For most residents, however, tephra will be a nuisance and can be mitigated by such actions as shutting down and covering equipment, frequently replacing air filters in machinery, wering dust masks and avoiding unnecessary travel." I gather these problems occur-- if at all-- only during small explostions on Mt. Hood, which seem to be extremely rare, and then only in a limited area.

[hamellr]

If it ever becomes a problem, there will be an emergency broadcast about it being a problem.

The last time we really had issues with that was when Mt. St. Helens went up.

[PNW-type-gal]

Other than ash fall during an eruption, the biggest tephra (tephra is a collective term for volcanic particles released during an eruption, from ash up to chunks of rock and pumice) hazard is in some hiking areas, where the layers of ash and pumice are pretty thick and hiking through them in the summer can kick up a lot of dust. It's not really like, say, vog on the Big Island in Hawaii where it can be a constant airborne threat.

[BayAreaHillbilly]

Of course the prevailing wind is westerly so that greatly reduces the issues in Portland (or any where to the south and west).

[wanderbygrace]

Originally Posted by Samoi137

Anyone in the Portland area ever have problems with tephra, perhaps during small explosions? USGS Web site says "minor amounts of tephra can make breathing difficult for those with respiratory problems, the elderly, and infants. For most residents, however, tephra will be a nuisance and can be mitigated by such actions as shutting down and covering equipment, frequently replacing air filters in machinery, wering dust masks and avoiding unnecessary travel." I gather these problems occur-- if at all-- only during small explostions on Mt. Hood, which seem to be extremely rare, and then only in a limited area.

First of all, Mt. Hood hasn't erupted since about the time Portland became a city over 150 years ago, so no one on here has any experience with Hood's eruption of anything. Same with Mt. Adams (last eruption long before white people ever came to North America). Occasionally on very cold & very clear days, you will see a rather small plume of steam hovering just above the summit of Hood (saw it once around January this year), but that is from the active fumaroles in the crater, and not from any eruption.

Only St. Helens has had eruptions in recent history, and if my readings have been correct, it's only been a couple of occasions where the wind has been blowing towards PDX during an eruption (rare, since the wind usually blows anyting from the MSH area away from Portland), and the city received any ashfall. My understanding is that it was rather light ashfall, and not much more than a significant annoyance.

[Minervah]

I can remember a few times when the ash blew from St Helens towards Portland and made breathing difficult after the volcano erupted. But wearing a mask was sufficient enough to protect someone. Ash did settle all around some points, so when the wind blew it stirred it up but it didn't happen often and it didn't stay around for long.

I remember being downtown and the wind was pretty heavy one time. The ash blew around forcing people to go inside and take cover but again, it was only for a short time. I have asthma so yes, it was a problem for me that day.

People were collecting it like mad for souvenirs.

[Larry Caldwell]

When St. Helens dusted the Willamette Valley it was more than a nuisance. Farmers lost millions of dollars worth of combines to the abrasive ash. It was interesting hauling wheat and seeing pieces of combine come out of the truck with the grain. My dad had to take his apart and completely rebuild it the next winter, including replacing much of the sheet metal.