The Meteorology and Hydrology Department on Monday warned people to be alert to the possibility of thunderstorms, lighting, isolated heavy rainfall, gale-force winds and hailstones caused by dense cumulus clouds in April and May. Generally, thunderstorms mostly occur in April and May in Myanmar. But, this year has seen early untimely weather patterns across the country. The change of weather patterns in Myanmar could be due to global warming. With global warming, the evil effects of natural disasters related to climate change are threatening the safety of our planet. There are increased occurrences of natural disasters with greater destructive impact. The consequences of climate change can cause physical and mental damage. It is obvious that we need to be ready to resist and respond to natural disasters. Since 1980, the country has seen an increase in the number of thunderstorms. With rain showers, relief from ultra-violet (UV) rays will arrive in some parts of Myanmar, which have been experiencing dangerous UV index levels. Cumulus clouds form in the afternoon and evening across the country in the current pre-monsoon season as daytime temperatures increase. It was found that cumulus clouds have been forming in wider areas, including Ayeyawady, Bago and Yangon, in the past few years. Meanwhile, we have experienced more lightning and hailstorms from these clouds and we had more reports of people being killed by lightning strikes. The death toll from lightning strikes is expected to continue to rise year by year. There were also fatalities and injuries from strong winds. Most areas across the country have experienced lightning and strong winds during the day due to high temperatures. We should switch off electrical appliances such as televisions and mobile phones when there are rainstorms with thunder and lightning. Gale-force winds which tend to follow heavy rainfall hit parts of Myanmar every year, destroying homes and toppling trees. Flash floods kill people and animals every year, and twisters caused by cumulus clouds are also seen every year. In April and May, with more rain showers, people should be alerted to flash floods, landslides, gales, lightning and hailstones due to cumulus clouds. Operators of vessels in rivers in those areas should be alert to tornadoes that can occur during thunderstorms.