Rainboots, sturdy rainboots...
Just keep an eye out on the news and phone weather aterts, not to mention your surroundings. Water tends to crest rapidly, in a matter of seconds, you could find yourself in the middle of a flashflood. Keep your wits about, reach higher ground wherever you are. Avoid power lines/poles, though. Yes, in the city. Look at the folks in Keelung, Zizhi, Neihu, etc. to mention recent cases. It takes seconds from the time you feel the water at your feet to when it is up to your shoulders.
Do not try to cross any water body you cannot see the bottom. If you fall in the middle of the street, for example, you could be pulled by the current down an unovered manhole or rain ditch. And then it is a nice sea burial for you... if they find you.
If you have to, do not go into the water with bare feet. Any open wound in such filty waters will infect easily and we really do not want to list/discuss what is in those muddy waters. Snakes and alligators are the least of your worries here.
That said, if possible, regardless we have the day off or anything, usual typhoon precautions apply -noodles, bread, tuna, granola, gallons of water for drinking baths brushing teeth cooking and most importantly comode- plus extra for thunderstorms -unplug appliances, prepare batteries and torches, etc.