Officials cautioned residents of Gulf states savaged by Isaac about high temperatures Tuesday as more than 100,000 are without power as rebuilding began. Lightning and heavy rain forecast for the next few days could add to the woes of those still dealing with the aftermath of flooding, CNN reported. \"We need everyone to take their risk of heat stroke seriously,\" said Bruce D. Greenstein, secretary of the Louisiana Department of Health and Hospitals. \"This is a serious condition that can kill you.\" The National Weather Service warned Monday that the areas of Louisiana and Mississippi most devastated by Hurricane Isaac could experience heat index values of 100 to 105 degrees. Those same areas could expect scattered thunderstorms through Saturday that could produce \"frequent lightning and heavy downpours,\" the weather service said. While the rain might relieve some of the oppressive heat, it was not welcome news otherwise. Officials in St. Tammany Parish northeast of New Orleans are still dealing with swollen lakes and rivers. Along the Mississippi state line, the Pearl River was projected to crest Tuesday at more than 5 feet about flood stage. A weak lock on an adjoining canal was being monitored. After visiting the area Monday, President Obama pledged to work to prevent similar flooding in the future, the Los Angeles Times reported. \"What I pledge to these folks is to make sure at the federal level we\'re getting on the case very quickly\" to figure out \"what exactly happened here ... and make sure it doesn\'t happen again,\"Obama told officials and affected families. Eight deaths along the gulf have been blamed on Isaac. More than 100,000 people are still without power nearly a week after the storm\'s landfall. Some 2,800 remained in shelters because of flooding.