Flooding Inwards Eastern Washington, Driest May On Tape For Western Washington
If you lot similar dramatic contrasts, Washington State offers a world-class example--and I am non talking virtually politics.
Over eastern Washington a number of rivers are at alluvion stage, roughly reaching tape levels.
Over eastern Washington a number of rivers are at alluvion stage, roughly reaching tape levels.
Thunderstorms in addition to heavy pelting convey been pummeling the Columbia Basin in addition to northeast WA. The National Weather Service has issued a alluvion alert for several counties including Okanogan, Bonner, Chelan, Ferry in addition to Pend Oreille, in addition to the Kettle River, which flows through Ferry in addition to Stevens counties, had a tape high on May 10 of 22.54 feet on May 10, busting the previous tape of 21.1 feet inward 1948.
In contrast, over the west, many locations convey had niggling atmospheric precipitation inward May, in addition to at that topographic point is adventure Seattle volition convey its driest May on record.
Not dark in addition to white. But dry out in addition to really wet. But why? And is jump flooding inward eastern WA unusual?
Let's origin yesteryear checking out the flooding situation, alongside information from the NOAA/NWS River Forecast Center inward Portland (below). Red dots are floods, bluish dots indicated moderate floods, in addition to royal are major floods. And several other locations are at bank-full.
What is going on? The combination of a salubrious mount snowpack in addition to warming temperatures, resulting inward rapid melting of snow, in addition to the filling of regional rivers.
Here is the snowpack numbers for Apr 15th, from the really prissy SNOTEL spider web site. Washington, northern Idaho, in addition to Montana had snow-water amounts good virtually normal...in roughly locations inward a higher house 150% of what is typical.
And snowpack inward British Columbia, from which the Columbia River drains was too really high (see table)
So going into jump alongside a bountiful jump snowpack was stride 1.
Then a combination of warming temperatures in addition to increasing jump solar radiations caused rapid snowmelt. The difference of average temperatures from normal (below) shows our temperature anomaly (difference from normal) for the yesteryear 2 weeks, alongside much of eastern WA in addition to northern Idaho beingness 6-8F inward a higher house normal for that period.
So the normal rapid snowmelt of jump was supercharged yesteryear warmer than normal temperatures.
But similar a late-night commercial, I should authorities annotation that there's more. The conditions designing has produced wetter than normal conditions eastward of the Cascade crest (and drier than normal to the west)--see map below of the atmospheric precipitation difference from normal for 5/3-5/16.
During the yesteryear few days, showers in addition to thundershowers convey moistened eastern Washington (see radar icon for iii PM yesterday), alongside the terminal 24-h totals beingness impressive. Influenza A virus subtype H5N1 number of locations inward northeast WA convey gotten over one inch during the terminal day.
So why moisture eastward of the Cascades in addition to dry out west? Because at that topographic point has been a persistent ridge of high pull per unit of measurement area along the coast, alongside troughs (low pressure) moving into California in addition to northward into eastern WA in addition to Idaho (see upper level--500 hPa--map for five PM Th to illustrate.) The ridge has kept western WA dry, piece the transient troughs convey initiated thunderstorms eastward of the Cascade crest.
It is of import to authorities annotation that spring-time flooding inward eastern Washington in addition to along the Columbia is the normal nation of affairs inward our region. Before the Columbia in addition to Snake River dams were inward place, major in addition to oftentimes catastrophic flooding was commonplace.
One of the most famous events was the groovy snowmelt alluvion of May 1948. Just equally inward this year, regional mount snowpack was inward a higher house normal, unusually warm temperatures hitting during mid-month, in addition to thunderstorms dampened eastern Washington. Richland flooded in addition to the surge of H2O moved downwardly the Columbia, inundating in addition to destroying the metropolis of Vanport (near Portland), which was never rebuilt.
As global warming reduces the regional snowpack afterwards during this century, the threats of such springtime flooding should gradually spend upwards over time.
In contrast, over the west, many locations convey had niggling atmospheric precipitation inward May, in addition to at that topographic point is adventure Seattle volition convey its driest May on record.
Not dark in addition to white. But dry out in addition to really wet. But why? And is jump flooding inward eastern WA unusual?
Let's origin yesteryear checking out the flooding situation, alongside information from the NOAA/NWS River Forecast Center inward Portland (below). Red dots are floods, bluish dots indicated moderate floods, in addition to royal are major floods. And several other locations are at bank-full.
What is going on? The combination of a salubrious mount snowpack in addition to warming temperatures, resulting inward rapid melting of snow, in addition to the filling of regional rivers.
Here is the snowpack numbers for Apr 15th, from the really prissy SNOTEL spider web site. Washington, northern Idaho, in addition to Montana had snow-water amounts good virtually normal...in roughly locations inward a higher house 150% of what is typical.
And snowpack inward British Columbia, from which the Columbia River drains was too really high (see table)
So going into jump alongside a bountiful jump snowpack was stride 1.
Then a combination of warming temperatures in addition to increasing jump solar radiations caused rapid snowmelt. The difference of average temperatures from normal (below) shows our temperature anomaly (difference from normal) for the yesteryear 2 weeks, alongside much of eastern WA in addition to northern Idaho beingness 6-8F inward a higher house normal for that period.
So the normal rapid snowmelt of jump was supercharged yesteryear warmer than normal temperatures.
But similar a late-night commercial, I should authorities annotation that there's more. The conditions designing has produced wetter than normal conditions eastward of the Cascade crest (and drier than normal to the west)--see map below of the atmospheric precipitation difference from normal for 5/3-5/16.
During the yesteryear few days, showers in addition to thundershowers convey moistened eastern Washington (see radar icon for iii PM yesterday), alongside the terminal 24-h totals beingness impressive. Influenza A virus subtype H5N1 number of locations inward northeast WA convey gotten over one inch during the terminal day.
So why moisture eastward of the Cascades in addition to dry out west? Because at that topographic point has been a persistent ridge of high pull per unit of measurement area along the coast, alongside troughs (low pressure) moving into California in addition to northward into eastern WA in addition to Idaho (see upper level--500 hPa--map for five PM Th to illustrate.) The ridge has kept western WA dry, piece the transient troughs convey initiated thunderstorms eastward of the Cascade crest.
It is of import to authorities annotation that spring-time flooding inward eastern Washington in addition to along the Columbia is the normal nation of affairs inward our region. Before the Columbia in addition to Snake River dams were inward place, major in addition to oftentimes catastrophic flooding was commonplace.
One of the most famous events was the groovy snowmelt alluvion of May 1948. Just equally inward this year, regional mount snowpack was inward a higher house normal, unusually warm temperatures hitting during mid-month, in addition to thunderstorms dampened eastern Washington. Richland flooded in addition to the surge of H2O moved downwardly the Columbia, inundating in addition to destroying the metropolis of Vanport (near Portland), which was never rebuilt.
As global warming reduces the regional snowpack afterwards during this century, the threats of such springtime flooding should gradually spend upwards over time.
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