4th Wettest “Water Year”

October 1, 2017

9pm Sunday

October is here and that means we have just wrapped up a “Water Year”.  So what is THAT?

Here’s the deal…our rainy season is late October through March; during the cool season.  As you know, we have a very dry warm season here compared to areas east of the Rockies.  That’s May through September.  All that winter rain and snowmelt is used to sustain our lives/properties/crops through the dry season.  So it’s important to know how wet our rainy season is each year.  But one rainy season crosses from the end of one calendar year into the first part of the next calendar year.  So for the purposes of ranking our wet seasons, we use a “water year”.  That year begins on October 1st and ends September 30th.  Make sense?

This last rainy season was VERY wet.  51.45″ in Portland and of course far more in the mountains.  We typically get around 36-37″ precipitation in the city each year so we gained a solid 15″ more rain than what we’d typically see

This season was the 4th wettest, behind 1996-1997, 1995-1996, & 1955-1956.  The highest on record was 58.67″.  The flooding in February, November, and a bit at the end of December pushed that year into the #1 spot.

Of course last year was a weak “La Nina” year so we expected higher than normal rain, but not THAT much rain!  It’s interesting that the dead of winter (December/January) was drier than normal due to the cold weather.  If we’re down around freezing we’re not getting the usual mild/wet systems coming through.

Snowfall in the Cascades ended up well above average up above 4,000′ and near average at pass elevations.  It’s about what we’d expect in a weak La Nina winter, although note Government Camp just barely reached a “normal” year.  The reason the ski season was so great down low was because the dead of winter was colder than normal and the good snow hit right away in late November and December.

We’ve got lots of sunshine ahead the next few days…this October is looking FAR different from last year’s washout.  We only had 3 dry days the entire month last year plus ZERO clear days.  We’ll easily exceed both of those stats in this first week of the month.

Chief Meteorologist Mark Nelsen