Monday, January 14, 2013

Salmon Ice Jam

(Update @ 8:45 am 01-26-13)


Ol' Man Winter finally released his cold grip on The Salmon Valley.  Temperatures are back in tolerable territory.  Although it's not exactly tropical, the rise in temps brought a welcome end to the relentless growth of The Salmon Ice Jam.   Water levels at the USGS gauge dropped almost as soon as the temps rose, a sure sign the ice jam let up a little.

The area isn't out of the woods yet as far as ice jam problems go.  Here's what the Missoula NWS has to say about the situation:


* ICE JAMS ON THE SALMON RIVER CONTINUE TO REMAIN IN PLACE
  BETWEEN CARMEN AND SALMON IDAHO. MULTIPLE ICE JAMS EXISTS ON
  THE LEMHI RIVER BETWEEN TENDOY AND SALMON.

* TEMPERATURES ARE WARMING THROUGHOUT THE SALMON AND LEMHI
  VALLEYS. THESE WARMING TEMPERATURES HAVE LEAD TO ICE JAM
  BREAKS ALONG THE LEMHI RIVER...CREATING SHARP RISES IN RIVER
  LEVELS. ICE JAMS NEAR TENDOY COULD CAUSE WATER TO BACK UP OVER
  HIGHWAY 28. WATER BEHIND THE ICE JAMS ON THE SALMON RIVER ARE
  CONTINUING TO CAUSE MINOR FLOODING OF FIELDS AND CAMPGROUNDS.

(Update @ 3 pm 01-24-13)  Below are three photos taken today by IDFG's Salmon Region Office Access Coordinator Greg Painter.  Greg went to check on the new Carmen river access point and graciously shared three photos with us.  THANK YOU, Greg!


We have put in two photos from this summer for comparison.  Comments are below each photo.
 This is the view across the brand new concrete boat ramp looking downriver toward the Hwy 93 Carmen Bridge.  The area in the foreground shadow is the approximate location of the boat ramp.
This is a photo taken from roughly the same location in June 2012 before the concrete ramp was finished.
Believe it or not, this is the upper end of the expansive parking area for the new Carmen access site!
Note the small cluster of black cottonwoods in the background just to the right of center.
Here's a photo taken last summer looking in the same direction as the picture above. 
Look carefully and you will see the same cluster of cottonwood trunks in the upper center of the photo.
 Finally, here's a view looking upriver from the Carmen access site.  
Unfortunately, we don't have a summer photo from this viewpoint.
It's entirely possible that the lingering affects and aftermath of the ice jam 
may cause spring fishing to come a little later this season.



(Update @ 7:30 am 01-24-13)
The Missoula NWS Office made a real nice graphic to put on the front page of their website.
The NWS Office noted: "The ice jams on the Salmon River near North Fork to south of Carmen and on the Lemhi River near Tendoy will continue to grow due to very cold temperatures. Flooding continues in low lying areas, campgrounds and fields near the rivers. Flood watches are in effect due to the potential for additional flooding."

Boise State Public Radio did a small piece on the ice jam yesterday.  Here is the link to their story:
http://www.boisestatepublicradio.org/post/flood-watch-near-salmon-effect-after-frigid-temps

(Update @ 3 pm  01-23-13)

Very cold overnight low temps have aided growth of the 2013 Salmon River Ice Jam. During super cold weather, ice jams often become part and parcel of Salmon, Idaho's "way of life."

The Missoula NWS has continued to issue a Flood Watch for Salmon, Idaho, for the past few days.

A persistent high pressure ridge has daily inversion layers that trap cold air on valley floors.  Salmon, Idaho and its namesake river have been below zero each night for over a week, ironically while overnight low temps in the nearby mountains have often been much warmer.  Here is the Salmon daily temperature graph for the past seven days.


The deep freeze fosters ideal conditions to form what known as "frazil ice," the chief culprit ice jams of this type.  For a technical discussion of frazil ice see this Wiki: http://en.wikipedia.org/wiki/Frazil_ice

The large area of slack water aptly named Deadwater creates a near-perfect initial ice jam that begins to capture frazil ice floating downriver.  It is successive additions of the frazil ice that cause the overall ice jam to expand upriver.  Under certain conditions, frazil ice can actually sink to the bottom. This natural aspect of frazil ice can be conducive to creating a natural dam in the river, thereby forcing river water to over top river banks at the head of the jam in an effort to flow around the jam.

The behavior of this type of ice jam can cause the river flow to fluctuate widely even with the same daily water volume.  Notice the USGS gauge in Salmon, Idaho, as it rises and falls as much as a foot each day during this current cold spell.
As of Monday, Leslie May Shumate reported the ice kam was within 1.5 miles of Salmon.  You can read her latest report by clicking here: http://lmshumate.com/article.php?article_id=2586

A January 22nd article in "The Post-Register" by Laura Zuckerman reported, "Weather observers said the deep freeze, predicted to continue at least until Wednesday, may increase the likelihood of flooding in some areas. But they said only time would tell.
    “We don’t know for sure. It may increase the potential for more field flooding, possibly causing water to back up a bit more,” said Mike Johnson, meteorologist with the National Weather Service office in Missoula, Montana.

The Salmon, Idaho, community has struggled for many years largely without success to find ways and means to mitigate the periodic ice jams.  The US Army Corps of Engineers became heavily involved with the ice jams back in the 1980's.  We have embedded one of the USCOE papers about the problem here.  Interested readers can find more such engineering discussions online.

(Editor's Note: You may read the PDF below with the online viewer or you may easily download it to your computer.)

(Update @ 12:22 pm 01-20-13)

The Missoula NWS issued their update a few minutes ago. We noticed the mention of the campground and called the Lemhi County Sheriff's Office. The BLM Morgan Bar campground is beginning to have some minor flooding in the low lying areas of that recreation site.

 The Sheriff's Office also reported water is encroaching into the flood plain across the Hwy 93 from the Carmen Post Office. The Sheriff's official said the Ice Jam hasn't reached Carmen Bridge yet but public safety officials are expecting it to reach the bridge and continue building upriver toward Salmon City in the next few days.

 The NWS meanwhile has issued a revised weather forecast that indicates potential for sub zero weather to continue to mid week. Such conditions are conducive to continued growth of the ice jam.

Below is the 12:06 pm Missoula NWS advisory.


1206 PM MST SUN JAN 20 2013

...FLOOD WATCH IN EFFECT THROUGH LATE TUESDAY NIGHT...

THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A

* FLOOD WATCH FOR A PORTION OF NORTH CENTRAL IDAHO...INCLUDING
  THE FOLLOWING COUNTY...LEMHI.

* THROUGH LATE TUESDAY NIGHT

* AN ICE JAM ON THE SALMON RIVER CONTINUES TO GROW BETWEEN CARMEN
  AND SALMON IDAHO DUE TO THE EXTENDED PERIOD OF EXTREMELY COLD
  TEMPERATURES. THE MINIMUM TEMPERATURES ARE ANTICIPATED TO REMAIN
  BELOW ZERO THROUGH WEDNESDAY MORNING. RIVER LEVEL OBSERVATIONS
  IN SALMON IDAHO STEADILY RISE AND MIGHT REACH FLOOD STAGE BY MID
  WEEK.

* THE SHERIFF OFFICE HAS REPORTED A CAMPGROUND NEAR CARMEN IDAHO
  BEING FLOODED. THE STEADY GROWTH OF THE ICE JAM WITH RISING RIVER
  LEVELS HOMES AND ROADS NEAR THE RIVER ALONG HIGHWAY 93 COULD BE
  FLOODED OVER THE NEXT COUPLE OF DAYS.
------------end of 12:22 pm update-----------


Another cold morning dawned in Salmon Sunday with the temp at 8 below zero.  The 7-day temp graph above shows just how persistent the cold low temps (in red) have been over the past five mornings.

Even though overnight lows aren't expected to go below zero in the upcoming week, temps look likely to continue to be low enough to continue building the ice jam.  Here's what the Missoula NWS forecasters had to say at 3:30 am this morning:


"High pressure will strengthen over the region beginning tonight into Wednesday. This will help reinforce and strengthen valley inversions. The main impacts will be for cold temperatures, worsening air quality, and periods of valley FOG. In addition, ice formation on area rivers and creeks will continue. Of most concern is the Salmon River near Salmon where the current ice jam is expected to continue to grow and could cause flooding concerns early this week due to the backup of water. Tuesday is expected to have the strongest inversions and thus the coldest temperatures of the week."

---------------Below is yesterday's Missoula NWS advisory on the Salmon Ice Jam--------------


The Missoula NWS continues to issue advisories about the Salmon Ice Jam. Here is their latest advisory from Saturday afternoon (January 19th, 2013). See notes below NWS advisory.

 HYDROLOGIC OUTLOOK NATIONAL WEATHER SERVICE MISSOULA MT 140 PM MST SAT JAN 19 2013 ...SALMON RIVER ICE JAM CONTINUES TO GROW CAUSING CONCERN FOR FLOODING... VERY COLD TEMPERATURES ARE FORECAST TO PERSIST THROUGH THE WEEKEND. OVERNIGHT LOW TEMPERATURES IN SALMON THE LAST THREE NIGHTS HAVE BEEN -9 TO -11 DEGREES AND ARE FORECAST TO REMAIN IN THE 0 TO -11 DEGREE RANGE THROUGH THE WEEKEND.

AS OF FRIDAY MORNING, THE ICE JAM WAS OBSERVED 4 MILES NORTH OF THE TOWN OF SALMON. THIS ICE JAM IS EXPECTED TO EXPAND AND POSSIBLY REACH THE TOWN OF SALMON BY MONDAY. WATER FLOWING DOWN THE SALMON RIVER MAY BEGIN BACKING UP BEHIND SECTIONS OF THE ICE JAM IN THE BIG FLAT AND CARMEN AREA AND COULD BEGIN TO APPROACH AND POSSIBLY FLOOD ROADS AND RESIDENTIAL PROPERTY IN THE NEXT FEW DAYS.
 ------------------------
The ice jam itself began in the Deadwater area downriver from North Fork. Ice jams are common in this area because of the slack water flow there. During periods of protracted deep cold, Deadwater area ice jams tend to grow and move upriver as they expand in area. That is how this year's ice jam is proceeding.

Salmon's fine LemhiWeb news sources currently carries a January 17th item about the ice jam by Leslie May Shumate. On January 17th Ms. Shumate said, "As of Thursday evening the Deadwater ice jam was in the Carmen Creek area and expected to reach the Carmen Bridge by tomorrow (Friday). If temperatures remain where they have been the ice jam is projected to reach the Salmon area by Sunday night or Monday."

The super deep freeze weather is predicted to modulate a little in the coming days.  Salmon's high temperatures are expected to be in the mid to upper 20's for a week before dipping back into the teens.  Low temps are predicted to reach the teens by Tuesday.  Sub zero temps do not appear in the forecast after tomorrow morning's low.

To read Ms. Shumate's full report click: http://www.lmshumate.com/article.php?article_id=2583

Below is the past 14 days of hourly temperature readings at the Salmon airport (KSMN).  The area's weather was great up until a week ago and then the bottom dropped out of the thermometer!  The past seven days has been brutal to the area and it's no surprise that the Salmon River Ice Jam has been growing upriver at a fast rate of speed. (Click on the graphic for a larger, more readable version.)

----------------------------
(Editor's Note: We will keep this article updated in the same manner we updated the Halstead Fire article this summer.  The newest material will be at the top.  The older material will be retained for reference.)
-----------------
Below is the first advisory that came out on January 14th. LEMHI- 432 PM MST MON JAN 14 2013 ...FLOOD WATCH NOW IN EFFECT THROUGH TUESDAY AFTERNOON... THE FLOOD WATCH IS NOW IN EFFECT FOR * A PORTION OF NORTH CENTRAL IDAHO...INCLUDING THE FOLLOWING COUNTY...LEMHI. * THROUGH TUESDAY AFTERNOON * AN ESTIMATED ONE MILE LONG ICE JAM IS MOVING THROUGH THE STRETCH OF THE SALMON RIVER THAT RUNS THROUGH THE CITY OF SALMON. A REPUTABLE RIVER OBSERVER HAS REPORTED QUICKLY RISING WATER LEVELS AS A RESULT OF THIS ICE JAM. * IMPACTS: THE MAIN STREET BRIDGE IN SALMON (HIGHWAY 93)... AS WELL AS HOMES AND STRUCTURES NEAR THE BANKS OF THE SALMON RIVER (NEAR THE CITY OF SALMON)... ARE UNDER THREAT OF MINOR FLOODING. We will attempt to determine how this ice jam is affecting the area.

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