Sunday, March 6, 2011

Iceberg Charts - challenging safe navigation

Sample of an iceberg chart

  • The estimated iceberg population density provided within the area bounded by the Iceberg Limit is for information purposes only and is not intended for navigation.

  • NAIS reconnaissance is focused near the Grand Banks of Newfoundland and the East coast of Labrador.  Ice conditions south of Greenland are not monitored by NAIS.  Icebergs in this area are not included on this chart.

  • These letters are for NAIS internal use only

  • The ICEBERG LIMIT is denoted by the solid line and represents the estimated extent of iceberg population based on recent reconnaissance and computer simulated iceberg drift. Drifted iceberg positions have an area of uncertainty that is fully encompassed by the Iceberg Limit.

  • NUMBERS represent the total number of icebergs including; growlers, bergy bits, and radar targets, whose estimated position is within the respective area bounded by one degree of latitude and one degree of longitude.

  • The SEA ICE LIMIT is denoted by the dashed line.  It is determined by CIS and  represents the estimated extent of at least 1/10 sea ice coverage.  The Sea Ice Limit is valid for 1600 UTC on the day prior to the date on the chart.  More recent and detailed sea ice info is available from CIS.

  • STATIONARY RADAR TARGETS will not be used to establish the iceberg limit but still represent a potential hazard to the Mariner. Therefore, when a stationary radar target’s estimated position is outside the Iceberg Limit, the radar target symbol will be used in the estimated position to represent the potential hazard.

  • The NOTE / NOTER block will be used to indicate if a special situation applies to the chart.  Examples include a chart revision (when  information is received that affects the accuracy of the chart), a significant (defined as at least one degree of change from the previous Iceberg Limit) expansion or a significant reduction of the Iceberg Limit.

  • The chart will be updated each day by 12:00 UTC and when changing ice conditions require a revision. For additional ice information please visit IIP at

    Daily chart:

    Do not confuse the above ICEBERG CHARTS with the below SEA-ICE CHARTS

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