Historic Rainy Day In Portland

December 7, 2015

9pm Monday…

2.69″ rain so far today at PDX.  That’s the wettest December day you’ve lived through!  It’s also ties for the wettest day ANY month of the year:


In case you are thinking…”wait a minute…I’ve seen it wetter than this!“.  Yes, you are right; it has definitely been wetter in a 24 hour period but not by much!  Two other times in the past 20 years we’ve seen more than the 3.22” we’ve seen in the past 24 hours.


This will go down as the 3rd wettest 24 hour period.

Notice I said PDX.  Official Portland records have been taken at the airport since 1940…so about 75 years.  There are older records from various locations downtown, but that area tends to be wetter than PDX (by 15-20% in the wet season) so we’d be comparing apples/oranges.  Plus, we only get observations from that location once per day, no hourly info, and no calendar day info.  That’s why we always talk about PDX.

Here are the other totals from today in the metro area and the rest of the FOX12 viewing area.

Surprising numbers at Hood River and The Dalles!  Good news for you folks.  A soaking is always welcome out there.

The big issues today were mudslides and small creeks.  All sort of sliding and high water.  Johnson Creek hit its highest level ever this afternoon at 15.33′  That even beat out the 1996 flood.  That’s due to the intensity of the rain, definitely not the duration.  Here’s a mudslide just off I-84 on Corbett Hill Road…precarious position to be in!


What happens the next few days?

One more warm/wet system tomorrow night, then more typical “colder systems” for the end of the week and the weekend.

I DO NOT expect a repeat of the 2-3″ totals tomorrow night.  More like 1.00″ to 1.50″ as this time it moves through pretty quickly.  Here’s the RPM forecast, which tends to be too wet often.


More wind too, although not too crazy.  Should be similar to this afternoon’s wind.

We’re still looking for a huge snow dumping in the Cascades as those colder storms arrive starting Thursday.  I think the real ski season begins this weekend and early next week.  That should include the lower elevation resorts too.  Not bad for mid-December!

Chief Meteorologist Mark Nelsen

Too Much Rain: Midday Storm Update

December 7, 2015

11am Monday…

Whew…too much rain in too short a time this morning;  much like Halloween.  Approaching 2″ of rain leading up to 9am and then suddenly  3/4″ in the past two hours ending at 11am at PDX.  Storm drains and small creeks aren’t used to that intensity of rain.  Lots of views like this all across the Portland/Vancouver metro area:

And rain totals since midnight:


As of 11am:  It’s the wettest December day on record at PDX!  2.36″ since midnight and almost 3″ since yesterday evening when the rain began.

The wettest calendar day on record is 2.69″ on Nov. 19, 1996.  The wettest 24 hour period is much heavier…4.44″ in late October 1996.  We may break the first record, definitely not the 2nd.

Obviously this is causing all sorts of “urban” (street/creek/home) flooding.  I wouldn’t be surprised to see more significant mudslides the next 48 hours as well.  If you live near a known mudslide area be alert to any movement!

Two main points for the rest of the day

1. RAIN WILL CHANGE TO LIGHT SHOWERS IN THE NEXT 2 HOURS, then light rain off/on through Tuesday afternoon.  Another slug of heavy rain arrives tomorrow evening/night

2. GUSTY WIND ARRIVES NEXT FEW HOURS.  Not damaging (probably) but enough to topple a few trees with water-logged ground.  Gusts 25-35 mph likely

CASCADE SNOW:  Forget about it…rain is even heavier up there washing the snow away.

RIVER FLOODING:  Looks like we’ve got at least 7 rivers under flood warnings.  Good news for the Willamette River system is that reservoirs are just about empty right now!  But that doesn’t help the small rivers/creeks or the coastal basins since they aren’t covered by flood-control reservoirs.