Bangkok has tried to remain a dry metropolis as the rest of Thailand experiences the worst flooding in 50 years, but as waters rise, the city's 12 million people could soon be inundated.

The power of the water is more than the flood barriers and water gates can withstand, Prime Minister Yingluck Shinawatra said Tuesday night. Thailand's military has been constructing sandbag flood-walls around the city for a week, but citizens are moving to higher ground as reports indicate that the barriers won't be enough.

The amount of water is gigantic, Yingluck added. “There is a high possibility that water will break into inner and central Bangkok as well as outlying areas.

The scale of the damage in Bangkok, which sits on the Gulf of Thailand, depends on the stability of a number of key areas that, if flooded, will spread water through the city.

If the three spots ... remain intact, the situation will improve. However, if we can't protect one of the spots, then the surrounding areas will be flooded. In the worst case, if we can't protect all three spots, all of Bangkok will be flooded, said Yingluck, who estimates that anywhere between four inches and five feet of water could swamp the capital, according to CBS News.

One of these areas is the embankment of the Chao Phraya River, which runs through the city. Currently, the Thai Navy has sent 10 ships into the Chao Phraya and other rivers and is hoping that constant propeller motion can slow the speed of the water flowing through the city, Voice of America reported.

The government has declared a five-day holiday in Bangkok and Thailand's other affected areas, which make up about a third of the country. Many residents are using the time to stock up on goods and to leave their homes. Thousands of people have already left, especially in the outskirts of Bangkok, where flood waters are waist-high. Schools will be shut until Nov. 7.

Water run-off has shut down Bangkok's two major airports. All-domestic fights on Nok Air have been delayed until Nov. 1, and a number of international flights have been canceled.

However, Bangkok's main international airport, Suvarnabhumi, is still open, and has had to accommodate an influx of flights previously scheduled to land at Don Muang airport.

The flooding began at the start of monsoon season in July, and three months of rain have ravaged Thailand's crops and caused billions of dollars in damages. So far, 373 people nationwide have been killed.

The rainy season has also affected Laos, Cambodia and Vietnam, where nearly 10,000 people have had to leave their homes.