Bethel Census Area, AK

In effect from Friday 09/18 4:14 PM AKDT – Saturday 09/19 9:00 PM AKDT

Issued by NWS Anchorage AK

ESFAFC

High water in the Kuskokwim River region will continue over the next few days. Conditions are expected to become favorable for water levels to gradually recede over the weekend and into the middle of next week.

Locations:

* Communities across the lower Kuskokwim River and its tributaries, including, but not limited to: Kwethluk, Bethel, Oscarville, Napaskiak, Napkiak, Kasigluk, Nunapitchuk, and Atmauluak.

Hydrologic Concerns:

* High water in the Kuskokwim and other area rivers (e.g. Kwethluk River, Johnson River, etc) may inundate low-lying areas in the aforementioned communities, nearby fish camps, and other lowlands.

Details/Analysis [What's causing this?]:

* Rainfall: The Kuskokwim River basin, from the mouth at Kuskokwim Bay upstream to the headwaters in the Alaska Range and Kilbuck Mountains, has received approximately 150 to 200 percent of normal rainfall this summer (June to August). These rains have continued into September, with nearly the entire basin near or exceeding 200 percent of rainfall, with much of that rainfall occurring over the last few days.

* Persistent High Water: This heavy rainfall has resulted in anomalously high water levels being routed down from the Upper Kuskokwim to the Lower Kuskokwim. The river gages at McGrath and Crooked Creek are near or exceeding record levels for this time of year. The water levels at these stations have crested in the last week, suggesting that the water inflow to the lower Kuskokwim Communities may be on the decrease soon.

* Compounding Factors: In addition to the recent rainfall and elevated river levels, strong coastal winds brought several feet of surge to the coast, causing elevated water levels near the mouth of the Kuskokwim River. This effectively reduces the slope of the river, slowing drainage and resulting in water becoming backed up.

* Forecast Thoughts: A shift in the weather pattern will bring conditions favorable for water levels to decrease. Northerly winds will increase Saturday and continue into early next week to 20 to 30 kt, with higher gusts possible at times, and bring cooler and drier air to the region. Precipitation will be sparse and generally light. Additionally, tidal models indicate a slight negative surge along the coast due to the multi-day period of strong northerly winds, potentially assisting drainage of water from the lower Kuskokwim River.

Look Ahead:

* After a period of weather conditions favorable for receding water, confidence is growing that another strong Bering Sea storm will affect western Alaska late next week (Sept 23-26). A return to southerly winds and higher coastal water in conjunction to heavy rainfall may exacerbate river conditions once again, particularly on the smaller tributaries such as the Kwethluk and Johnson Rivers. However, details remain uncertain at this time as confidence is low in storm track and intensity. Fortunately, natural tidal cycles in Bethel and the rest of the lower Kuskokwim favor lower tides than usual for this timeframe which may offset any additional water or surge.

---

---