Felleng formed as a tropical storm over the southern Indian Ocean on January 26, 2013, and strengthened into a cyclone on January 29. That day, the U.S. Navy’s Joint Typhoon Warning Center (JTWC) reported that Felleng was located roughly 420 nautical miles (780 kilometers) north of Réunion Island. The storm had maximum sustained winds of 90 knots (170 kilometers per hour), with gusts up to 110 knots (205 kilometers per hour). Over the next 36 hours, wind speeds were forecast to increase to 115 knots (215 kilometers per hour) with gusts up to 140 knots (260 kilometers per hour).
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this natural-color image of Felleng off the east coast of Madagascar on January 29. The JTWC projected storm track showed Felleng moving southward over the Indian Ocean, east of Madagascar and west of Réunion, then veering slightly toward the southeast. Although the center of the storm was expected to remain off Madagascar’s coast, storm clouds could easily extend over the eastern reaches of the island.