ALASKA RIVER AND LAKE ICE INFORMATION FORM
We request your assistance on obtaining information on ice conditions on rivers and lakes in your area. We would appreciate it if you would fill in any of the information in the form below. Your help contributes to a more complete record of river ice information for Alaska. See instructions (in a new window) for observing river ice for terminology and maps with river miles (in a new window)
Observation position Aerial obs Ground obs
Enter your e-mail address or an e-mail address where we may contact you if we have questions (optional)
Date of observation: (required) Name: (optional)
Time: Phone: (optional)
Location: (Fill in as much information as necessary to locate the observation location)

Name of river or lake:
Nearest community or landmark: Miles from nearest city/landmark: Direction from nearest city/landmark:
Enter any additional information about location below such as a reach of river between two points
Enter as much of the following information as possible for your current observation
Ice conditions prior to and in early stages of breakup
Ice thickness: If ice covers the entire channel and an estimate of the average ice thickness is known enter it here in inches, along with method used to obtain the thickness. Thickness:
Condition of ice (Check all that apply) Snow Covered Water on Ice No Snow Hard Ice Rotten Ice
Predominant color of ice observed: (Check all that apply) Green or blue White Gray Brown or blackOther (specify):
Ice cover status prior to breakup Unbroken (ice still frozen to shore with few cracks) Arched ice cover (ice raised in center causing meltwater to collect on ice surface along both shorelines)
Lifted sheets (ice sheets broken free from shore ice by rising water with no ice shifting) Shifted sheets (ice sheets broken free from shore ice by rising water and shifted their position in the river channel) Open reach (sheets shifted downstream leaving an open reach)
Enter any early breakup remarks here:
Moving ice characteristics
Amount of stationary ice along the banks: estimate the width of the band of shore ice in feet or percent of river width (e.g. 5% of river width on left bank and 15% of river width on right bank): Left bank (looking downstream):
Right bank (looking downstream):
Ice run density (the estmate is most accurate if you can look down from a high view point... it is easy to overestimate the ice coverage when viewing from ground level) Heavy (75-100%) Moderate (25-75%) Light (1-25%)
Size of moving ice: (Check all that apply) Sheets Pans Chunks
Ice run speed compared to the speed of the normal river flow. Very slowly Slowly Average Fast
For ground observations, provide time the ice run began and ended at your location: Time ice run started:
 Time ice run ended:
 Note whether water level is rising or falling:
For aerial observations, provide location of downstream end of ice run: Time:
 Latitude or River Mile:
 Longitude:
 Estimated length of ice run:
Enter any ice run remarks here:
Ice jam characteristics
Provide location of ice jam: Time:
 Latitude or River Mile:
 Longitude:
 Estimated length of ice backed up by jam:
Cause of ice jam
(Check all that apply)		 Solid Ice Sheet Constriction in channel River bend Island Other
Enter other details about jam such as flooding upstream etc
Post breakup characteristics
Ice run density (provide information on post breakup ice runs as these are navigation hazards) Heavy (75-100%) Moderate (25-75%) Light (1-25%)
River status: (check all that apply) Ice free flow Stranded ice on shore
Enter any additional remarks here:
Thanks for your help!
River Forecast Center 907-266-5160

National Weather Service
Alaska-Pacific River Forecast Center
6930 Sand Lake Road
Anchorage, AK 99502

FAX 907-266-5182
Return to the RFC Homepage without submitting the form