The unusually heavy rains have created havoc across an area ill-prepared for them, unleashing torrents and floods that have swept away entire villages, according to some reports. Road links across the province have been cut, making both communication and rescue work extremely arduous, witnesses said.
Some of the worst impact of the disaster has been seen in the southwestern district of Kech, around 400km west of Karachi and with a population of some 750,000 people.
The nearby Soorab Dam burst its banks, and water flowing downstream reportedly entered the town of Turbat on 28 June. Waves of water quickly swamped it. Panic-stricken people in the area took shelter on the roofs of tall buildings, including mosques, and in the hills.
The larger Meerani Dam, on the River Dasht, 30km southwest of Turbat, is said to be in a precarious situation and there are fears it could overflow. Local authorities on 28 June began moving people to higher ground, while a state of emergency was declared in the worst affected districts.
Fears that other reservoirs could be flooded have led to thousands across the province fleeing their homes. "The whole province is in crisis," Farid Ahmed, the provincial coordinator for the Human Rights Commission of Pakistan (HRCP), told IRIN in Quetta.
Some 250,000 people affected
"About 250,000 people have been affected by the rains and the cyclone. We are trying to send in what help we can using helicopters," provincial relief commissioner Khuda Baksh Baloch told IRIN.
Twenty four people have been reported dead in the province as a result of the floods, but there are fears the number could rise dramatically as the fate of missing persons becomes clear. Reports say that river waters have swept away entire villages in the Turbat area.
A passenger bus carrying a wedding party to Buleida, to the north of Kech District, has reportedly vanished and is believed to have been washed away. At least 30 people were travelling on the bus.
"Vast tracts of Balochistan are affected. It is impossible to communicate with areas either by land or by telephone. The towns of Dadhar, Gandawa and Jhal Magsi, lying between 100 and 280km southeast of Quetta, are all under water because of burst reservoirs or hill torrents," Farid Ahmed said.
There was "panic" across the province, with people in Quetta unable to contact their families in villages south of the provincial capital, he said.
Aisar Baloch, 35, a resident of Turbat currently visiting Quetta told IRIN his family members were "virtually marooned" and "no help has reached them". He said he was able to establish contact over a mobile phone.
There are also reports that villages in the Mashkhel District, lying to the northeast of Balochistan on its border with Punjab, as well as in the Kharan District which lies south of Quetta, have been submerged.
Over 100,000 homeless
According to initial estimates, at least 100,000 people have been left homeless, but confusion and a lack of communication means district authorities have faced problems in compiling details.
A spokesman for the Balochistan government, Razik Bugti, said: "Army and navy helicopters are busy rescuing people from rooftops and other high areas."
Meanwhile high winds and rain meant that the sea along coastal areas remained turbulent. Ten boats were reported missing and with people feared drowned off the coast city of Ormara on 28 June, and dozens of others had been damaged.
"We are continuing to issue warnings and rescue people marooned along the coast or at sea," a spokesman for the Pakistan navy said.