After accumulation of frazil ices and crushed ices is formed, it will develop toward upper reach and also process slowly toward lower reach.
这个冰花与碎冰显著聚积体形成后即可向上游发展,也能向下游缓慢推移。
Ice jam flood: a lot of frazil ices and crushed ices gather under the covering ice, causing heading up of water level of upper reach.
冰塞洪水,大量冰花与碎冰在盖面冰下集聚,造成上游水位显著壅高的现象。
英语百科
Frazil ice
Frazil ice is a collection of loose, randomly oriented needle-shaped ice crystals in water. It resembles slush and has the appearance of being slightly oily when seen on the surface of water. It sporadically forms in open, turbulent, supercooled water, which means that it usually forms in rivers, lakes and oceans, on clear nights when the weather is colder, and air temperature reaches −6°C (21°F) or lower. Frazil ice is the first stage in the formation of sea ice.