Prime Minister Narendra Modi will be on a day-long visit to Bihar today to take stock of the flood situation in the state. <br/><br/>Mr Modi will undertake an aerial survey of the worst-affected bordering districts of Araria, Purnea, Katihar and Kishanganj. <br/><br/>He will also hold a review meeting with Chief Minister Nitish Kumar and other officials in Purnea. Sources said, the state government will submit a detailed memorandum to Mr Modi for a central assistance.<br/><br/>Over one crore seventy lakh people in 21 districts are affected by recent floods. 415 have, so far, lost their lives. <br/><br/>The situation continues to be grim in Muzaffarpur, Samastipur and Darbhanga. Urban areas of Muzaffarpur have been inundated following the breach of Tirhut Canal. <br/><br/>Turbulent water of Burhi Gandak is posing a threat to the embankment in Samastipur. Surging water of Bagmati is spreading in fresh areas in Darbhanga.<br/><br/>Rail traffic on Darbhanga-Samastipur section continues to be disrupted.