Storms generally occur in Bangladesh in the months of April-May and October-November.
The Meterological Department uses separate codes of signals for storm warnings at maritime and river ports. These codes are given below in abbreviated forms.
It should be noted that the signal numbers in the two codes do not carry the same significance and, in particular, that higher signal numbers within the danger and great danger maritime groups indicate differences in storm location not difference in strom intensity.
Storm warning signals for use at maritime ports.
a) Distant signals:
1. Cautionary. There is a region of squally weather in which a storm may be formed.
2. Warning A strom has formed.
b) Local signals:
3. Cautionary Port is threatened by squally weather.
4. Warning. Port is threatened by a storm, but danger not yet sufficiently great to justify extreme precautionary measures.
5-7 Danger Port will experience severe weather from a storm of slight or moderate intensity.
5. Storm expected to cross the coast to the south of the port.
6. Storm expected to cross the coast to the north of the port.
7. Storm expected over or near the port.
8-10 Great danger. Port will experience severe weather from a storm of great intensity.
8. Storm expected to cross the coast to the south of the port.
9. Storm expected to cross the coast to the north of the port.
10. Storm expected over or near the port.
Failure of communication. Communications with the Meteorological Warning Centre have broken down and the local officer considers that there is danger of bad weather.
Storm Warning Signals For Use At River Ports:
1. Cautionary. Area threatened by squally winds. Look out for further developments.
2. Warning. A storm or nor-wester is likely to strike the area.
3. Danger A storm will soon strike the area. All vessels seek shelter immediately.
4. Great danger A violent storm will soon strike the area.
Source: Meteorological Department.