Cyclones | Department of Meteorology and Hydrology

Cyclones

Cyclones in the Bay of Bengal usually form in April, May, October and November. During the monsoon season, small cyclones form in the North Bay of Bengal. Pre-monsoon and post-monsoon storms are very destructive and cause a lot of damage.

The three main destructive forces of a cyclone are strong winds, heavy rain and storm surge. When a cyclone crosses the Myanmar coast, the maximum wind speed is 120 to 130 miles per hour. This depends on the strength and size of the storm. The Department of Meteorology and Hydrology issues storm force conditions. A strong storm will have stronger winds, heavier rain and higher storm surges. The Rakhine coast and delta areas are areas at risk of cyclones, including Chin State, Shan State, Magway Division, Mandalay Division and Sagaing Region may experience heavy rain, flash floods and strong winds due to the passage of storms.

The Department of Meteorology and Hydrology monitors the storm situation day and night and issues advance warnings as the storm approaches land. Therefore, whenever a storm occurs, do not be overly concerned, but plan ahead and take precautions before, during and after the storm. By watching and listening to the storm news or storm warnings of the Department of Meteorology and Hydrology and cooperating with and following the guidance of local organizations, you can face and overcome the danger of a storm.

Notes on Storm Warnings

(1) Pay more attention to storm news during storms

(2) Whenever a storm occurs in the Bay of Bengal, be aware of the location of the storm that will approach the Myanmar coast

(3) When issuing a storm warning, please note that a storm warning is issued only for storms that are not dangerous to Myanmar and a storm warning is issued only for storms that are dangerous to Myanmar.

(4) Please pay special attention to the following points included in the storm warning:

- Distance from the location of the storm to your residence

- Distance from the path of the storm to your residence

- Type of storm, distance from the area where the storm is expected to pass

- Time of storm occurrence and tides, tidal nature of your location

Storms and damage that crossed the Myanmar coast

No	Date	affected area	Damage
1	May 14-17, 1884	Sittwe	Over 100 people died, many crops were lost and losses worth 200 million kyat were incurred.
2	April 22-26, 1936	Kyaukphyu	About 1000 people died, over 7000 buffaloes and cows died and 2000 million kyats worth of damage was caused.
3	October 6-8, 1948	Sittwe	Some people died, property worth 100 million was lost.
4	October 22-24, 1952	Sittwe	Four people died in Yangon, Sittwe and Pathein suffered extensive damage and losses of 10 million kyat were reported.
5	May 15-18, 1967	Kyaukphyu	Over 100 million kyat was lost in Pathein District and over 200 million kyat was lost in Kyaukphyu District.
6	October 20-24, 1967	Sittwe	90% of houses were destroyed in Sittwe, 100 million kyat was lost, 2 people died, Rathedaung and Kyauktaw were destroyed by 90% and over 100 people died in Monywa district and over 1000 cattle and cows died.
7	May 7-10, 1968	Sittwe	(1037) people died, (17537) cattle and cows died, (57663) houses were destroyed, (100) lakhs worth of damage was caused and the storm surge reached (4.25) feet.
8	May 5-7, 1975	Pathein	(303) people died, (10,190) cattle and cows died, (246,700) houses were destroyed, (776.5) million kyats worth of losses the storm surge reached (3) feet.
9	May 12-17, 1978	Kyaukphyu	90% damage in Kyaukphyu, 200 million kyat loss
10	May 4, 1982	Gwa	Damaged (90%) in Gwa
11	May 2, 1994	Maungdaw	Damage estimated at 500 million kyat and the storm surge reached (3.66) feet.
12	April 29, 2006	Mala (Gwa)	One person died and the storm surge reached 4.57 feet.
13	May 2-3, 2008	Nargis (Ayeyarwaddy)	(138,000) people died, (13) trillion kyats were lost.
14	October 20-23, 2010	Giri (Rakhine)	45 people died, 0.024 trillion kyats worth of losses
15	April 14-16, 2017	Maarutha (Thandwe)	-
16	May 25-29, 2018	Deep Depression (Ann)	-
17	March 15-23, 2022	Deep Depression (GWA)	-
18	May 19-21, 2022	Depression (Mawlamyine)	Loss of 33245,000 kyats
19	May 8-14, 2023	Mocha (Sittwe)	151 people died, 29,958 were injured and affected, and more than 30 billion kyats worth of damage was caused.

Storm surge

1. As a storm approaches the coast, large waves suddenly rush inland with strong winds and then the waves roll back into the sea, carrying away life, buildings and property.

2. Storm surge can be higher in the water column and can travel inland through coastal estuaries.

3. It usually occurs on the right and downstream side of the storm track a few hours before the storm hits the coast.

Cyclone Hazard

Since Myanmar, including the Bay of Bengal, the northern Indian Ocean and the South China Sea are geographically located in the tropical zone, storms that form in these seas are considered tropical storms.

The following conditions are required for a tropical storm to form:

(a) There must be a large area of sea/ocean with sufficient water vapor.

(b) The sea/ocean surface temperature must be at least 26.5°C or higher.

(d) Atmospheric instability must be present in the lower levels of the atmosphere.

(e) Above the area of lower-level atmospheric instability, the air must diverge outward.

When storms occur, the following three types of destructive impacts may result:

strong winds, heavy rainfall and storm surge.

Before the storm season hits

1. Listen carefully to forecasts and warnings.

2. Identify the nearest storm shelter and find the fastest route to get there safely.

3. Don’t listen to rumors.

4. Prepare an emergency kit in advance containing essential items.

5. Inspect your home thoroughly and reinforce any weak structures to ensure stability.

6. Trim or remove branches and trees around your house and yard that could break during strong winds.

7. If your area is prone to storm surge, identify and prepare safe shelter locations such as higher ground or cyclone shelters.

8. Keep the phone numbers and addresses of emergency services, rescue teams and information centers readily accessible.

9. Store dry food, essential medicines, and appropriate protective supplies.

10. Conduct preparedness training for emergency search and rescue operations.

When a Cyclone is Approaching / Occurring

Disconnect all electricity supplies and gas pipelines.
If strong winds may cause the building you are sheltering in to collapse, take cover under sturdy tables or beds, or hold firmly onto a strong pillar or support.
When cyclone warnings indicating severe conditions are issued, do not go out to sea for fishing.
Move to cyclone shelters as quickly as possible.
Continuously monitor the latest updates and warnings via radio.
Remain in a safe location until the authorities officially announce that the cyclone danger has passed.
If you are driving when the cyclone strikes, stop the vehicle. If you are away from the sea and clear of large trees, power lines, and reservoirs, remain inside the vehicle.

After the Cyclone

Do not go outside until the authorities officially announce that the cyclone danger has passed.
Check for any gas leaks and avoid using electrical appliances that are wet.
Pay close attention to announcements and advice issued by the authorities.
Do not return to your home until the relevant authorities advise that it is safe to do so. If returning is permitted, use only the designated routes so that rescue operations can be carried out efficiently.
If traveling by land, be particularly cautious of snakes.
Avoid touching or handling fallen electrical wires along roadsides and report them to the nearest electricity office.
Be cautious of fire hazards.
Take precautions against diarrheal diseases.
Assist in rescue and relief operations where possible.

Hazards Caused by Cyclones

Strong winds may damage trees and buildings.
Sudden drops in air pressure may cause breathing discomfort.
Very high waves may occur in the open sea.
Large waves may surge into coastal areas; when coinciding with high tide, storm surges and waves may inundate coastal regions.
Lightning may damage or dry out trees.
Saltwater intrusion may contaminate wells and damage agricultural lands.
Heavy rainfall may cause flash flooding.
Waterborne diseases and illnesses such as diarrhea, colds, and fever may occur.

Cyclone Information and Warnings

“Cyclone Information” - Issued when there is no threat to Myanmar.
“Cyclone Warning” - Issued when there is a threat to Myanmar.

Storm Category

No	Storm Category	Wind speed (miles per hour)
1	Low Pressure Area (LPA)	< 20
2	Depression	20 – 31
3	Deep Depression	32 – 38
4	Cyclone	39 – 54
5	Severe Cyclonic Storm	55 – 72
6	Very Severe Cyclonic Storm	73 – 137
7	Super Cyclonic Storm	≥ 138

Color Coding of Cyclones by Strength and Direction

(1) Yellow Emergency Stage

A yellow emergency is defined as the time when a storm begins to form in the Bay of Bengal and the Andaman Sea. When a yellow emergency is declared, it is broadcasted on Myanmar Voice and City FM approximately (2) to (3) times per hour and on Myanmar Television and Myawaddy Television during the daily weather bulletins. This emergency indicates that a storm is beginning to form in the Andaman Sea or some part of the Bay of Bengal.

(2) Orange Emergency Stage

A yellow emergency is defined as the time when a storm begins to form in the Andaman Sea and Bay of Bengal and is moving towards the Myanmar coastline. In this case, Myanmar Voice and City FM will broadcast the yellow emergency about (3) to (4) times per hour and Myanmar Television, MRTV4 and Myawaddy Television shall broadcast the storm warning with real-time subtitles and frequently on the intermission program.

(3) Red Emergency Stage

The period of time (12) hours before the storm moves towards the Myanmar coast and crosses the Myanmar coast is considered a red emergency. In such a case, storm warnings containing the above information shall be broadcasted on the Myanmar Voice about (3) to (6) times per hour, and on the Myanmar Television, MRTV-4 and Myawaddy Television with real-time subtitles and frequently on the intermission program.

(4) Brown Emergency Stage

The period of time when the storm crosses the Myanmar coast is considered a brown emergency. In such a case, storm warnings shall be broadcasted on the Myanmar Voice about (3) to (6) times per hour and on the Myanmar Television, MRTV-4 and Myawaddy Television, MRTV-4 and Myawaddy Television shall broadcast the weather forecast frequently with real-time subtitles.

(5) Green Condition Stage

The time when the storm has weakened and the danger of the storm has passed is considered to be a green condition. It shall be broadcast frequently about (2) to (3) times an hour after the storm passes. Myanmar Television, MRTV-4 and Myawaddy Television shall broadcast the weather forecast frequently with real-time subtitles.

(6) 24-hour news coverage

A radio station or radio channel shall be established to provide (24)-hour weather coverage to the public. This channel shall broadcast weather news 24 hours a day as well as weather specials as needed.

Myanmar Cyclone Season

Myanmar has two cyclone seasons, the pre-monsoon season from mid-April to May and the post-monsoon season from October and November. Cyclones usually form in the Bay of Bengal and initially move west or northwest. Sometimes they change direction to the north or northeast, causing storms to enter Myanmar. During the mid-monsoon season (July to August), they form in the northern Bay of Bengal and move only to the northwest coast of India. During the late-monsoon season (September and October), storms that form in the South China Sea cross the coast of Vietnam and the remnants of the storm move westward and reach the Andaman Sea, where they re-form as storms.