As of 21 November, an estimated 622,000 Rohingya refugees fled Myanmar to Bangladesh. The influx began on 25 August, after the Myanmar Army launched security operations in northern Rakhine state. In September, an average of approximately 14,500 people arrived daily. This dropped to an approximate average of 3,100 arrivals per day in October. The estimated number of people in need was 1.2 million in the latest Humanitarian Response Plan (HRP) of October 2017. This number was comprised of the pre-existing caseload of Rohingya in Bangladesh (government estimates of 300,000), the new influx since 25 August (at 509,000 on 3 October), people in host communities (300,000), and a contingency for a further 91,000 people.