"serious rainfall" is a correct and usable phrase in written English.
You can use it to describe a large amount of rainfall in a short period of time. For example, "We received an especially serious rainfall last night, resulting in localized flooding."
The one serious bit of rainfall last week started in the half-hour before the handicap in which he was due to carry top weight, giving 25lb or more to his 16 rivals.
Nevertheless, competition for water in AF remains a serious challenge where rainfall is too low to recharge soil below the crop rooting zone unless tree roots have access to deepwater reserves.
However, a high incidence of leptospirosis was observed in Pingtung, where flooding caused by Morakot was most serious (maximum cumulative rainfall >2,500 mm).
The operational models showed deficiency and serious under-prediction in rainfall amount at real time.
Further investigation and enquiry revealed that these related to a serious episode of unseasonal rainfall followed by drought with consequent food insecurity.
A large number of water bodies and wetlands have become derelict in the region due to lack of adequate rainfall posing a serious threat to the biodiversity, especially the livelihood of the poor and marginal people, of the area.
Niger is facing a severe food crisis resulting from erratic rainfall in 2009, which caused serious shortages of both cereals and fodder.
Mr. Turner added that one tornado had touched down in the area and that the rainfall could become quite serious.
KCNA and international aid groups have drawn attention to the low rainfall that could have serious impact on the DPRK's agricultural sector, threatening its already fragile economy.
The amount of rainfall predicted could bring serious hazards, and the storm presents something of a test run in the busiest part of hurricane season.
