Five days after one of the worst typhoons on record hit the Philippines, the magnitude of the catastrophe is barely captured in the preliminary statistics: nearly 2,000 people listed as dead and many thousands more missing; more than 600,000 people displaced; countless homes and roads crushed by surging water.

News photographs of the dead lying in city streets are heartbreaking. Relief efforts are facing serious obstacles as huge numbers of survivors grow desperate for food, water, medical care and shelter. The situation is so bad that Filipino troops have been deployed to Tacloban, the devastated coastal capital of Leyte Province, to guard against unrest.

The United Nations has called for more than $300 million in aid, and many reliable past donors — the United States ($20 million), Japan ($10 million), Australia ($9.3 million), Britain ($16 million) — are again proving generous. One exception is China, the world’s second-largest economy after the United States. China is at odds with the Philippines over claims to the South China Sea and has offered a paltry $200,000. But delivering relief supplies to victims has been severely hampered by impassable roads, a collapsed infrastructure and, reportedly, a shortage of aircraft capable of landing on a short runway.

President Obama offered on Tuesday to provide American help as quickly as possible. The United States has already dispatched an aircraft carrier with 5,000 sailors along with more than 80 aircraft and four other ships, which are expected to arrive in two or three days. Britain has also sent warships. But even heavy-duty help does not guarantee a successful response, and Philippine officials came under criticism on Tuesday for moving too slowly.