Under SOLAS, Chapter 5, Regulation 2, Masters are obliged to communicate information on navigation dangers. Such dangers include the following:

(a) dangerous ice;
(b) a dangerous derelict;
(c) sub-freezing air temperatures associated with gale force winds likely to cause ice accretion;
(d) gale force winds of storm force 10 or above, for which no report has been issued;
(e) any other direct danger to navigation;
(f) such danger messages must contain the nature and position of the danger, together with the time and date of observation.