Houston is one of Americas top ten riskiest places to visit in terms of natural disasters.
Due to its proximity to the coast, the Gulf of Mexico and residing just beneath Tornado Alley, Houston is subject to a lot of storms, hurricanes and tornados. The mixture of humidity and fluctuating temperatures means that there are a lot of thunderstorms too.
If there is a storm or hurricane warning, the usual advice is to shelter in place. Unplug electrical items, stay away from windows and, depending on severity, take stock of what food and clean water you have access to. Ultimately, you should keep up to date with the local emergency news and follow their advice. As the weather changes, new information may come up so pay attention.
If you are told to evacuate, then do so immediately.