A trough of low pressure began to develop in the southern Chukchi Sea on August 11, 2012.  The trough developed into a closed low aloft near Wrangel Island by the 14th, and the low continued to wobble around in the Chukchi Sea through the 20th.  The low produced a long fetch of moist southwest flow aloft and combined with several surface lows and frontal boundaries to transport copious moisture into parts of the western Brooks Range, Chukchi Sea coast, and parts of the Seward Peninsula.

Extraordinary rainfall amounts were observed in a few spots.  The Red Dog Mine observed a 7-day storm total of 8.79 inches of rain, and a 9-day total of an amazing 10.38 inches, which is well in excess of half of the average annual rainfall.  Tahinichok Remote Automated Weather Station, which is located approximately 15 miles west of Noatak observed a 7-day rainfall total of 7.47 inches.  Kivalina, along the immediate Chukchi Sea coast observed a 7-day total of 4.93 inches.  Nome, which is along the southern Seward Peninsula, had a week long total of 3.74 inches.  A runway closure at Nome was compounded by the heavy rainfall, and caused seven Alaska Airlines flights to be cancelled and there were no cargo flights all week.
The Wulik River, which is one of only a handful of automated river gages in northwest Alaska, observed a record crest at 0500AKST on the 16th of 15.31 feet or 75,320 CFS.  This is the highest crest observed since the gage was installed in 1985.  The old record high crest was 12.21 feet on August 17, 1994. By comparison, prior to the heavy rain the river was flowing at only 1,250 CFS or only about one sixtieth of what was observed after the heavy rainfall.  Somewhat lighter rain continued to fall after the crest on the morning of the 16th which led to additional crests on the 17th, 19th and 22nd. At the peak crest on the morning of the 16th, the USGS estimated that the Wulik River gage had at least 6 inches of water in the gage house.  The river would be well above bankfull and likely spread out one half to one mile overbank on the west side of the river.  A hunting lodge downriver from the gage was likely under 3 to 4 feet of water.
The high volume of water draining from the Wulik and nearby Kivalina River filled the Kivalina lagoon faster than it could drain out to sea on August 16th.  This resulted in an unusual flooding scenario in the village of Kivalina. The water level on the lagoon rose to the point where it was topping over the lower banks and getting under some houses, and washed over the village dump site. The high water damaged the pipe that runs between the village and the intake at the mouth of the Wulik River. Very turbid water from the high flows prevented the village from pumping fresh water which led to a water shortage in the village, and bottled water had to be flown in.  The water shortage cancelled the start of the school year as the school and teacher housing was without clean water.  It was estimated that the school may not open until October 1st.
At Kotzebue, waves estimated at 4 feet high in the lagoon sank one boat that had its bow on the beach but the back end filled from the breaking waves.  The water levels begin to fall on the morning of the 17th.
On the afternoon of the 16th the Red Dog Mine reported that the water levels were high and creeks were overbank and flooding. Culverts were at full capacity and there was some slumping of roadways around the mine. Otherwise, the mine reported no significant impacts or damages to their infrastructure.

Flood in LOWER KOBUK & NOATAK VALLEYS, ALASKA
From 15-AUG-12 21:00:00 to 17-AUG-12 03:00:00 (AKST-9)
Location: NOATAK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Other Federal Agency

Flood in CHUKCHI SEA COAST, ALASKA
From 16-AUG-12 18:00:00 to 17-AUG-12 18:00:00 (AKST-9)
Location: KIVALINA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Flood in BALDWIN PEN. & SELAWIK VALLEY, ALASKA
From 16-AUG-12 12:00:00 to 17-AUG-12 12:00:00 (AKST-9)
Location: KOTZEBUE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee