Floods in Yakutsk occur on a seasonal basis due to proximity of the city to the Lena River. Ice break-up on Lena in mid-May causes ice jamming in the lower parts of the river, which can significantly reduce the flow and cause upstream flooding. Wildfires take place on a seasonal basis due to a dry climate in summer with low precipitation levels (under 200 mm per year), exacerbated by repeated man-made accidents. The boreal forest vegetation type found in the region mainly consists of highly flammable Siberian larch trees, and is prone to fire particularly in May and June. Fires can also occur in July and August during drought periods.