Flooding is the primary weather-related hazard faced by Roanoke. Heavy rains, most frequently from remnants of a hurricane, drain from surrounding areas to the narrow Roanoke Valley. The most recent significant flood was in the fall of 2004, caused by the remains of Hurricane Ivan. The most severe flooding in the city's history occurred on November 4, 1985, when heavy storms from the remnants of Hurricane Juan stalled over the area. Ten people drowned in the Roanoke Valley and others were saved by rescue personnel. Many residents complain that they are prone to allergies because of pollen from trees in the surrounding mountains. Most famously, the family of Wayne Newton moved from Roanoke to the dry climate of Phoenix, Arizona, because of his childhood asthma and allergies. However, there have not been clinical studies to establish that these conditions are more prevalent in Roanoke than in other cities with similar vegetation and climate. Within its boundaries, Roanoke is divided into 49 individually defined neighborhoods. Interstate 581 is the primary north-south roadway through the city. It is also the only interstate highway as Interstate 81 passes north of the city limits. Interstate 581 is a concurrency with U.S. Route 220, which continues as the Roy L. Webber Expressway from downtown Roanoke, where the I-581 designation ends, south to State Route 419. Route 220 connects Roanoke to Martinsville, Virginia and Greensboro, North Carolina. The proposed Interstate 73 would generally parallel Route 220 between Roanoke and Greensboro and would likely be a concurrency with I-581 through the city. The primary east-west roadway is U.S. Route 460, named Melrose Avenue and Orange Avenue. Route 460 connects Roanoke to Lynchburg. U.S. Route 11 passes through the city, primarily as Brandon Avenue and Williamson Road, which was a center of automotive-based commercial development after World War II. Other major roads include U.S. Route 221, State Route 117 (known as Peters Creek Road) and State Route 101 (known as Hershberger Road). The Blue Ridge Parkway also briefly runs adjacent to the city border. Roanoke is divided into four quadrants: Northwest (NW), Northeast (NE), Southwest (SW) and Southeast (SE). The mailing address for locations in Roanoke includes the two letter quadrant abbreviation after the street name. For example, the Center in the Square complex in downtown Roanoke has the address "1 Market Square SE".