For persons with disabilities, information should be provided in accessible formats. If such vulnerable groups are not adequately informed and supported, the system as a whole must be judged to have failed. Rapid onset disasters such as near-field tsunamis and flash floods only allow between 15 minutes and a couple of hours from detection to impact, so the warning system should be able to respond to imminent danger. Other hazards, such as cyclones and seasonal floods, may be detected days or even weeks in advance - allowing people to protect assets and livelihoods (Figure III-2).