It appears to have been extraordinary luck for the boatmen that their 

 skiff came sufficiently close to the Faloon that they could dive across 

 and pull themselves out of the water onto the larger boat. After start- 

 ing the engine, approximately 5 minutes after the earthquake, they saw 

 a huge wave, building up behind the lighthouse and heading out of the 

 Narrows. It overtopped the lighthouse about 2 minutes later. They 

 estimated the wave as 35 to 50 feet high in the Narrows and laden with 

 mud, timber, and other debris. The Falcon was overtaken by the wave 

 just outside the Narrows, but by then, fortunately, the wave had spread 

 laterally into Jack Bay and Valdez Arm (Figure l6o) and attenuated in 

 height, thus enabling the boat to ride over the top. Later they saw 

 many large waves, one right after the other, in the vicinity of the 

 mouth of the Narrows and Jack Bay (Chance, 1968). 



As envisioned in Figure I65 , it is believed that Valdez was subject 

 at about this time to a combination of successive waves which were prob- 

 ably the fundamental and binodal seiches for Port Valdez embodying the 

 periods of 17.8 and 9-8 minutes (Equation (^9)). Since the fundamental 

 period for Port Valdez is about the same as the second mode period (18 

 minutes) for the entire Valdez Arm, Narrows, and Port basin system 

 (Equation (^8) ) , we should expect that these waves gradually set the sys- 

 tem rocking in its fundamental mode of about 39 minutes (Equation ( U8 ) ) . 

 Figure I65 also expresses our belief that the first crest of the main 

 tsunami, generated at the mouth of Prince William Sound, would have 

 reached Valdez within about 30 minutes with rather insignificant ampli- 

 tude. However, the development of oscillations from within the embayment 

 and from without may be assumed to have developed a strong system of beat 

 oscillations, which is suggested in the later part of the inferred mari- 

 gram of Figure 165. The fundamental tsunami wave on the shelf, meanwhile, 

 in tune with the fundamental period (T - 110 minutes) of Prince William 

 Sound, may be expected to have built up the amplitude of oscillation of 

 about this period which penetrated into the Valdez embayment. These con- 

 ditions are shown in the marigram, which has been constructed basically 

 from eyewitness observations of the later waves, but with a foreknowledge 

 of the probable oscillating characteristics of the regime. 



After the first 25 minutes of horror, the waves reaching Valdez 

 on the low tide were not high enough to draw special attention, and 

 presumably failed to reach even normal high tide level. As the tide 

 rose, however, the oscillations in the Sound increased in amplitude, 

 and Valdez faced further destruction (Figure 165). 



Two large waves reached Valdez on the high tide during the night. 

 There is some discrepancy between reports as to their arrival times (Berg, 

 et al, 196i+; Chance, 1968); Coulter and Migliaccio, I966; Migliaccio, 

 I96U; Dunning and Gilson, SEA interview (1966). The reported crest times 

 for the first of these two waves vary from 10:30 to midnight and for the 

 second from 12:30 to 1:^5. However, the most likely times of occurrence 

 of the wave crests are ll:i+5 and 1:35, as suggested in Figure 165. 



282 



