Tropical Cyclone Chapala slammed into Yemen's central coast early Tuesday, lashing the area with maximum sustained winds of around 140 kph (85 mph).
But the major concern is the extraordinary volume of rain the storm is expected to dump on the country's dry, rugged terrain, bringing a severe threat of mudslides.
Yemen typically gets around 100 millimeters (4 inches) of rain per year. Chapala is forecast to unleash two to three times that amount in the space of just one day.
The deluge is likely to cause "massive debris flows and flash flooding," CNN meteorologist Tom Sater warned.
The storm made landfall not far from Al Mukalla, a port that al Qaeda in the Arabian Peninsula seized earlier this year amid the chaotic conflict engulfing Yemen.
The country isn't used to finding itself in the path of tropical cyclones.
Reliable records, which only go back about 30 years, show no landfalls by hurricane-strength tropical cyclones in Yemen. Chapala, which was the equivalent of a Category 1 hurricane early Tuesday, had at one point been the second strongest storm ever recorded in the Arabian Sea.
Most of the storms that brew in the Indian Ocean end up in the Bay of Bengal, on the eastern side of the Indian subcontinent. Those that do make their way across the Arabian Sea are more likely to hit Oman, which lies to the north and east of Yemen.
Chapala already brushed past Socotra, a Yemeni island in the Arabian Sea where 60,000 to 65,000 people live.
Abdul-Jamil Mohammed, deputy director of the Environmental Protection Authority on the island, reported strong winds, heavy rain and big waves overnight into Monday.
Mohammed said the storm damaged some homes and uprooted trees in Hadibo, the capital of Socotra. Contact has been lost with the northeastern part of the island since Sunday night, and floods have covered the roads leading there, he said.
"Our problem is we have no one to help us here," he said, explaining the island has one hospital and four ambulances.
Yemen is already dealing with one of the largest humanitarian crises in the world, according to the United Nations.