Shanshan was a tropical storm in the Philippine Sea on Thursday afternoon (Japan time), the Joint Typhoon Warning Center said in its latest warning.
The tropical storm had sustained winds of 46 miles per hour.
The typhoon season lasts all year round, but most typhoons form between early July and mid-December.
Most typhoons graze or hit areas such as the Philippines, Japan and Taiwan; they can also hit the Korean Peninsula, China and Vietnam, bringing destructive winds and storm surges.
Where will it rain?
Flash flooding can also occur inland and away from the storm center. Even weaker storms can produce excessive rainfall that can flood low-lying areas.
US territories have also been hit by typhoons that caused billions of dollars in devastating damage, such as Guam, which was hit by Super Typhoon Mawar in May last year.