North Atlantic icebergs are worst in the spring months. The Titanic hit an iceberg on April 15.
At present, the Boston ice chart is being updated once a week, but this will shift to daily before long. Note the distinctive callsign "NIK" used for the ice broadcasts. Here is the schedule for these (times UTC, frequencies kHz):
0438 FAX 4235, 6340.5, 9110
1218 SITOR 8416.5, 12579, 16806.5
1600 FAX 6340.5,9110
1810 FAX 6340.5, 9110.
And here's a typical chart copied a couple of days ago: