65 Years Ago Today: The Vanport Flood

May 30, 2013

65 years ago this weekend, Oregon’s 2nd largest city was erased from the map in hours.  If you’ve never heard of the Vanport Flood, read on…it only happened 5 miles from downtown Portland.

I love weather AND history, so I find this flood fascinating, especially since it’s results echo through Portland even in 2013.

During World War II (1940-45), huge numbers of workers were brought in to work in the shipyards here in Portland.  There was an urgent need for housing, so a city was quickly built and called VANPORT (Get it?  Vancouver+Portland?) on the flats north of Portland.  That’s the low area west of I-5 around Delta Park where PIR, Heron Lakes, and Delta Park West is now.  That city contained 40,000 at it’s peak, making it the 2nd largest city in the state!

After the war, lots of folks moved away, but there were still 13,000+ residents there by the Spring of 1948, three years after the war ended.  Even a college had opened in the city for the returning GI’s…the Vanport College.

The winter of 1947-48 brought massive snowfall to the mountains of the Pacific Northwest and Rockies, along with lots of rain.  At this time there were very few dams to hold back spring floods on the Columbia and Snake Rivers…although Grand Coulee and Bonneville Dam both were operational.  The Columbia River rose throughout May 1948 and by Memorial Day Weekend was approaching the 30′ level on the Vancouver gauge.  That’s within 4′ of the all-time high in 1894.  For comparison, that 1948 level is about 21′ higher than the river is on this Thursday afternoon!  The Portland Housing Authority had put out a notice the morning of the flood saying:


That didn’t happen.  On Memorial Day, May 30th, (used to be on that date instead of the last Monday of May) the railroad dike on the west side of the city (where the railroad is now) burst around 4:20pm.  A 10 foot wall of water went surging into the city.  By sunset the city was inundated and remained so for over a month.  A few factors helped keep the death toll quite low (just 15):  it was the holiday weekend with lots of people out of town and mild temps plus bright daylight kept confusion to a minimum too I suppose.  Here’s the view two weeks later from just about the same vantage point.  Note the triangular are of trees on the edge of the slough in both pictures: 

Interesting to note that the river kept rising, and peaked about the date this picture was taken…at exactly 31′ on the Vancouver gauge.  The flood was the 2nd highest on the Columbia River since record keeping began in the 1800s.

Here are the results:

1. About 1/2 of the residents were of African-American descent; largely settling into north and northeast Portland following the flood.  Lots of  good information about this online which is way out of the scope of a weather blog, but really interesting.

2. Vanport College was called “the college that wouldn’t die”, restarted in downtown Portland, and became Portland State University.

3. The town wasn’t rebuilt, but became a raceway, a park, golf course, and wetlands.

4. The Flood Control Act of 1950 spurred more dam building along the Columbia and it’s tributaries, due to the 1948 flood.

Chief Meteorologist Mark Nelsen

A Very Wet May, But Summer Ahead

May 29, 2013

Last night’s soaking put us into a tie for 3rd place here in Portland.


As of 4pm we’ve seen 4.68″ 4.71″  so far…strangely enough that’s the same total from May 2010 (I think I added wrong initially), that was a gruesome late spring!  Here are the top 5:


Even stranger, this May total is just a quarter-inch away from the entire February, March, & April combined total!  Those were some very dry months.

I think I mentioned 2-3 weeks ago that we’d see payback for all that dry weather and sunshine…

So what happens next?  It’s as if a switch is going to go off and we go dry again.  Get ready for a return to summer, and this time it’ll be “real” summer weather (next week) because it’ll be June.

Why a dramatic change?  The cool upper-level troughiness and moist westerly flow will be replaced by an upper level ridge either over us or just to the west (reminds me of late winter and most of spring).  As we head into summer this pattern is usually dry with just varying degrees of onshore flow or flat onshore/offshore gradients.  Take a look at the rise in 850mb temps over the next week on the 12z GFS:


The 12z ECMWF is similar, although it appears the cold trough late next week is a big outlier (the blue line is the operational run):


850mb temps peak out around +15 or so next Tuesday/Wednesday/Thursday.  That should easily push us up into the low-mid 80s!  Our 7 Day is a little cooler because I’m a little gun-shy after some episodes earlier this spring.  Or maybe I’m just getting old and conservative with a cold-bias?  The new 18z GFS is even warmer with 6 days at +15 or warmer starting next Tuesday…Summer!

The ground is very wet right now, but should dry quickly the next 3-4 days with warmer temps.  I was out in my (overgrown) yard today…wow, lots of weeding, mowing and weed-whacking on the way.  But it sure is GREEN out there!  Can’t wait to get outside in the sunshine and warmer temps, even if it involves a lot of work.

Chief Meteorologist Mark Nelsen

Memorial Day Weather Action

May 27, 2013

What a horrid Memorial Day weatherwise!

A surface low pressure center offshore and a frontal system brought steady rain from daybreak through midday in NW Oregon and SW Washington.  East wind ahead of the front even gusted to 40 mph (50 on the steps?) at Vista House with the usual dense fog up in that area.  Then a breezy south wind kicked up behind the front as a few lines of showers and thunderstorms developed  during the late afternoon.  Here’s a view of 5 of the strikes in Clark County:


As of 4pm Portland’s rainfall for the day is 0.64″, which is a new record for May 27th.  The old record is .59″ on May 27, 1990.


I almost always work Memorial Day weekend because someone else might want it off or more likely it’s just going to be cool and showery anyway.  I’d much rather “bank” the day and use it during summer.  Plus, no adults around (bosses), so we can be less productive and still not get fired…just kidding, mostly.

Showers continue overnight, then diminish tomorrow as we wait for another vigorous (for late May) system Tuesday night and Wednesday morning.  Then more showers Wednesday and early Thursday.

After that…finally, a change in the weather pattern.  The weak May storm track lifts a bit north Friday and Saturday, and maybe beyond.  It doesn’t take much to improve our weather in early June, so we’ll easily jump into the 70s over the weekend.  That’s good because the Rose Festival Starlight Parade is Saturday evening and I’m riding in a car with Shauna Parsons.  We don’t want our hair messed up of course.   By the way, make sure you wave.  Not sure how I scored such an exhausting “work day” Saturday, but I’ll take it.

HUGE DISAGREEMENT on models Sunday and beyond.  Take a look at the ECMWF and GFS ensemble charts.  Note that the line “3 JUNE” is Sunday afternoon the 2nd for a time reference:




The ECMWF says it’ll be somewhere between 0 and +18 by Monday afternoon.  That’s a high temperature somewhere  between 55 and 90 degrees.   By next Tuesday, the 12z GFS says somewhere between +3 and +23.  That’s 65-95!  What’s going on?  Take a look at the operational 12z ECMWF for next Monday morning, it shows a cool upper low (mainly dry) dropping over the top of a developing ridge (just to our west) and down into the Pacific Northwest.  It’s basically “crashing the ridge”.  The 12z GFS had no such thing, but it’s obvious many of its ensemble members think the ECMWF is correct since the 18z brings the upper low much closer.  I went with the ECMWF solution thus a much cooler forecast….we’ll see.

Chief Meteorologist Mark Nelsen




Quick Weekend Post

May 24, 2013

I’ve been extremely busy the past 36 hours.  Worked late Wednesday night, in bed at 1am, up at 6:30am.  Field trip with my son’s entire school (270 kids!) over to Wildhorse Canyon (the old Big Muddy/Rajneeshpuram ranch).  Volunteered, worked in kitchen for 5 hours, slept 4-5 hours in the same bunk room as 8 boys, drove 3 hours back this morning, now back at work…I’m toast.  So it’ll be a brief post.

In general the cool and wet weather continues for at least the next week.  It won’t be quite as chilly the next few days since the cold upper level low is departing this evening.  In fact snow levels will be above 6,000′ the next few days.  But still cooler than average.

There are hints on the ECMWF and GFS that some sort of warmer pattern may appear about 8-9 days from now (around next weekend).  If you follow the AVERAGE (red) line on the latest two ensemble charts it’s pretty obvious.  The 18z GFS was an outlier with its chilly solution beyond Day 9:




So maybe this is just a 3 week cool/wet period to be followed by a nice June…who knows.

My advice for the weekend?  BBQ, and then curl up in front of the fireplace and watch some Netflix.  I plan to sleep in…


On a side note, and since I’m a big fan of history…

I thought it was really neat to stand in the same ENORMOUS building where all those crazy folks and the Bhagwan had their huge meetings, and sleep in the same “hotel rooms” that were used back then.  The events that took place in that location and elsewhere across Oregon during those 5 years combined to make the biggest news story in our area in the past 50 years.  Anyone over 40 that lived in Oregon in the 80s knows what I’m talking about.  I doubt those people expected that 30 years later it would be full of screaming kids, sport courts, climbing walls, and a huge skatepark!

Chief Meteorologist Mark Nelsen


Record Cold May Day

May 22, 2013


A cold upper-level low combined with steady rain pretty much the entire day in most of SW Washington and NW Oregon has given us a record setting chilly May day:


  • 50 degrees (as of 5pm) just reaches the average low for this date
  • 50 degrees is the coldest daytime high for this date
  • 50 degrees is also the latest in the spring we’ve seen a 50 degree high temp
  • The coldest high temperature ever recorded in Portland in May was 49 degrees both in 1962 and 1964 (early in the month)

It only gets warmer after today (it can’t get colder right?), but it sure doesn’t get much drier.  Expect rain at times through next week.

By the way, MAYUARY is a combo of MAY/FEBRUARY (or January if you like).  After extensive input, I decided on that versus MAYVEMBER.

Chief Meteorologist Mark Nelsen

The Cold & Wet Weather Is Here

May 21, 2013

What a change this afternoon.  Take a look at the temperature change from 6pm Monday to 6pm Tuesday:


We were 23 degrees lower here in Portland!  Around noon I was doing some errands on the eastside of town, getting irritated at the lack of rain (I don’t like a bad forecast).  But that forecast turned out perfect this afternoon…what a downpour.  It was our first good soaking in about 4 weeks, very much overdue:


The cold upper level low has definitely arrived hasn’t it?  850mb temps over Salem this afternoon were measured between -2 and -3 degrees celsius.  That’s just about the core of the cold air, so it won’t get any colder than this.  The bad news though is that the upper-low isn’t going anywhere from now through Monday (Memorial Day).  That means we have a chance for showers through the Memorial Day Weekend.  The coldest/heaviest showers will definitely be tomorrow through Friday with the coldest airmass.

If you are looking for a return to some semblance of warmer weather, think again.  Take a look at the 850mb ensemble temperature chart from the 12z ECMWF:


Very good agreement that below average temperatures will likely continue for the next 10 days.  Monday and/or Tuesday will be close to average, but at that time we get into a wet westerly flow, so lots of gray.

Here’s the 00z GFS chart, very similar:


So put away the shorts & flipflops, keep the pool covered, and hope your warm weather veggies can tolerate some repeated soakings without rotting.

Chief Meteorologist Mark Nelsen

Oklahoma City Metro Area Tornadoes

May 20, 2013

As you all probably know, a huge tornado in the southern suburbs of Oklahoma City this afternoon.  For now it’s been rated at least EF-4.  Town names like Newcastle and Moore probably sound familiar to you if you follow weather.  That’s because a deadly F-5 tore through the same towns 14 years ago this month…May 3, 1999.

How do the paths compare?  I found this image online, but can’t find the source of the info.  I’m not a journalist, just a meteorologist, so I can get by with passing the info on to you as well without checking it’s source.  Looks pretty close to reality though:

nws moor tornado paths

Notice there is one neighborhood that appears to have been hit by both powerful tornadoes…the chance of that happening anywhere on this planet is VERY low.