Iceberg Chart

Example of an iceberg chart

  1. Numbers on the chart represent the total number of icebergs including growlers, bergy bits, and radar targets, whose estimated positions are within the respective area bounded by one degree of latitude and one degree of longitude. 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.
  2. NAIS reconnaissance is focused near the Grand Banks of Newfoundland and the east coast of Labrador.  North of 53°N, NAIS uses climatology along with less regular flights and satellite data to develop an Estimated Iceberg Limit represented by a dotted line.  This line represents a rough estimate of the current extent of the iceberg population in this region
  3. The Iceberg Limit is denoted by a solid line and represents the extent of the iceberg population based on recent reconnaissance and computer simulated iceberg drift and deterioration.  Drifted iceberg positions have an area of uncertainty that is fully encompassed by the Iceberg Limit.
  4. The Sea Ice Limit is denoted by the dashed line 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.
  5. Stationary Radar Targets will not be used to establish the Iceberg Limit but still represent a potential hazard to the Mariner. 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.
  6. The NOTE block will only indicate web addresses for more information.

If an iceberg is detected and reported outside the published NAIS Iceberg Limit, a Notice to Shipping (NOTSHIP) will immediately be sent by the Canadian Coast Guard Marine Communications and Traffic Service (MCTS) and an urgent NAVAREA IV message will be distributed over GMDSS by the National Geospatial-Intelligence Agency (The NAVAREA IV Coordinator).  These warnings will remain in effect for 24 hours. Iceberg products will be revised shortly after notification between 1200 UTC and 0000 UTC or by 1400 UTC the following day if reported between 0000 UTC and 1200 UTC.  No updates to the Iceberg Chart will be made between 0000 UTC and 1200 UTC.

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