def get_height(root):
    """Extracts the ash plume height - only valid for ash alerts!
    Values returned are in this order:
    1. Maximum ash height (kilometers)
    2. Maximum ash height (feet)
    3. Tropopause height (kilometers)
    4. Tropopause height (feet)"""
    hgt_km = root.alert.max_height.attrib.get('value')
    hgt_ft = root.alert.max_height_feet.attrib.get('value')
    tropohgt_km = root.alert.tropo_height.attrib.get('value')
    tropohgt_ft = root.alert.tropo_height_feet.attrib.get('value')
    return hgt_km, hgt_ft, tropohgt_km, tropohgt_ft