The reports of death in Asia are truly horrifying. But some early reports of the damage caused by the tsunami indicated that there was no warning. I think this will turn out to be untrue.
First, if you are near bodies of water and feel an earthquake, immediately move to higher ground. The earthquake that created the waves was of such magnitude that everyone would have felt it and the waves created would take several minutes to arrive.
Second, if you are near a body of water and the water rapidly drains from the shore, run immediately to higher ground as the waves will be arriving in a matter of seconds to a few minutes. Note that a tsunami is typically a series of waves and the first may not be the largest. Further, there may be gaps of several minutes or even hours between the waves.
Unfortunately, this part of Asia is not covered by the Pacific Tsunami Warning Center (PTWC) located in Ewa Beach, O’ahu, Hawaii.
The PTWC, using a series of water-level gauges placed around the Pacific Basin can track and predict the path of a Pacific-wide tsunami minutes after it is generated. Even though there were no such sensors in the part of Asia hit by the recent tsunami, the PTWC sent warnings, based on the magnitude of the earthquake, to Asian countries telling them of the possibility of immediate tsunami damage. Apparently, the warnings were not heeded.
For more information, see this site here.