National Weather Service United States Department of Commerce

Current PIREP observations requests: Link

National Weather Service (NWS) is responsible for monitoring ice breakup conditions throughout Alaska to assess flood threats and navigational hazards. Ground observations, aerial reconnaissance, and remote sensing are sources used to assess ice conditions. Although ice jam flooding is most common during the ice breakup season, ice condition reports are welcome during freezeup and mid-winter as well.

We have relied for many years on observations of Alaska village residents describing the river ice condition in front of the village. Supplemental aerial observations from aircraft flying at low to mid-level altitudes have significantly enhanced the information on ice conditions. Since ice conditions can vary significantly along a river and can change rapidly during the breakup process, numerous observations are needed statewide to assess the status of breakup. It must be stressed that we are looking for reliable and objective reports.

The River Watch Program is a voluntary program that is...

  • Asking pilots and village residents to provide reports of river ice conditions
  • Requesting pilot observations that can be obtained without deviation from the normal route or flight level
  • Stressing that river ice observations only be taken when it can be done safely
  • Serving the purpose to assist the NWS in providing accurate forecasts, warnings, and navigation information

River and lake ice observations can be provided to the Alaska-Pacific River Forecast Center (APRFC) via:

  • radio from aircraft to AFSS with observations for inclusion in a PIREP
  • phone at 1-800-847-1739
  • email report and/or photos to nws.ar.aprfc@noaa.gov

Additional information about the program and tools to download are available at the following links:

Program background:

Training materials:

Results:

Many thanks to the FSS, other partner agencies, commercial and private pilots, and village residents for their river ice observations during the ice breakup seasons.



 
STANDARD REMARKS
PRE-BREAKUP
  • UNBKN ICE
  • ARCHED ICE
  • LIFTED ICE
  • SHIFTED ICE
  • OPEN REACH
  • HARD OR ROTTEN ICE
  • SNOW OR WATER ON ICE
  • OPEN HOLES OR LEADS
  • FLOW IN SIDE CHANNEL
  • FLOW ON ICE
ICE JAM CONDITIONS
  • APPARENT ICE JAM
  • ICE JAM
  • VILLAGE AND/OR RUNWAY FLOODING
    (PRECEEDED WITH LOCATION NAME)
  • WIDESPREAD FLOODING
  • LOW LYING FLOODING
MOVING ICE
  • BREAKUP (BU) FRONT
  • ICE RUN
    >> MIXED
    >> SHEETS
    >> PANS
    >> CHUNKS
  • X MILE LONG ICE RUN
    (X = DISTANCE)
  • ICE RUN DENSITY
    >> HVY (75-100%)
    >> MOD (25-75%)
    >> LGT (1-25%)
POST-BREAKUP
  • STRANDED ICE
  • OPEN CHANNEL
  • ICE OR DEBRIS RUN
    >> HVY (75-100%)
    >> MOD (25-75%)
    >> LGT (1-25%)