Dahl naît en à Cosmopolis.
Le , une vedette garde-côte américaine, commandée par Harold Dahl, dans laquelle se trouvent également son fils (15 ans), son chien, ainsi qu'un autre membre d'équipage, patrouille au niveau de Puget Sound. Le jour est morne et sombre, avec des nuages bas.
Le bateau fait escale dans une baie de l'île Maury (Maury island), à environ 5
km de Tacoma. Les gens à bord de la vedette voient alors
vomit alors des fragments de métal en fusion qui tombent dans l'eau
et sur le rivage. L'un d'eux tue le chien, un autre brûle grièvement le fils de Dahl, et une mouette est également
tuée. Le bateau est endommagé. Puis l'ovni s'élève, rejoint les autres, et tous les 6 partent à toute vitesse
au-dessus du Pacifique. Les hommes recueillent des échantillons de métal encore chaud. De retour au port, Dahl
rapporte les événements à son officier supérieur, Fred Crisman.
Le lendemain matin, un homme vêtu de noir arrive chez Dahl dans une Buick noire et l'invite à déjeûner. Durant le repas, il déclare à Dahl être au courant de tout ce qui s'est passé à Maury et lui dit :
Le silence est la meilleure chose pour vous et votre famille. Vous avez vu ce que vous n'auriez jamais du voir.
Dahl établit plus tard que personne n'a parlé à qui que ce soit de leur étrange expérience.
Crisman promet de rappeler Arnold dès que le problème serait résolu. Il ne le fera jamais. Et ne rendra pas non plus les photographies. Il est devenu introuvable d'après Dahl, il a quitté la ville pour affaires; d'après d'autres sources, il a été vu pour la dernière fois montant à bord d'un avion militaire en partance pour l'Alaska.
Puis le fils de Dahl disparaît à son tour. De plus, il semble que quelqu'un ait truffé de micros la chambre d'hôtel de Kenneth E. Arnold, transmettant aux journaux locaux les détails de ses conversations, même celles qu'il eut seul avec Brown et Davidson. Il contacte un autre officier de renseignements de la base USAF de McCord, le major Sanders. Ce dernier l'emmène chez un fondeur de Tacoma (probablement Asarco à Ruton) et lui montre des scories commes les morceaux de Dahl et Crisman. Arnold ne les considère pas identiques. Lorsqu'Arnold souhaite en prendre un échantillon, Sanders le dissuade. Sanders demande tous les morceaux à Arnold et Smith. Après qu'il les ait mis à l'arrière de sa voiture, ils ne les renverrons plus jamais.
Le , Dahl raconte toute l'histoire à Arnold dans la chambre du Winthrop Hotel de Tacoma :
Le dans l'après-midi vers 14 h je patrouillais la Baie Est de l'Ile Maury près de la côte. Cette île pratiquement inhabitée se trouve directement opposée à Tacoma à environ 3 miles de la terre principale. Ce jour-là la mer était plutôt agitée et il y avait de nombreux nuages bas. En tant que capitaine, je dirigeait mon bateau de patrouille près de la côte d'une baie sur l'île Maury. A bord se trouvaient 2 hommes d'équipage, mon fils de 15 ans et son chien.
As I looked up from the wheel on my boat I noticed six very large doughnut-shaped aircraft. I would judge they were at about 2000 feet the water and almost directly overhead. At first glance I thought them to be balloons as they seemed to be stationary. However, upon further observance, five of these strange aircraft were circling very slowly around the sixth one which was stationary in the center of the formation. It appeared to me that the center aircraft was in some kind of trouble as it was losing altitude fairly rapidly. The other aircraft stayed at a distance of about two hundred feet above the center one as if they were following the center one down. The center aircraft came to rest almost directly overhead at about five hundred feet above the water.
All on board our boat were watching these aircraft with a great deal of interest as they apparently had no motors, propellers , or any visible signs of propulsion, and to the best of our hearing they made no sound. In describing the aircraft I would say they were at least one hundred feet in diameter. Each had a hole in the center, approximately twenty-five feet in diameter. They were all a sort shell-like gold and silver color. Their surface seemed of metal and appeared to be burled because when the light shone on them through the clouds they were brilliant, not all one brilliance, but many brilliances, something like a Buick dashboard. All of the aircraft seemed to have large portholes equally spaced around the outside of their doughnut exterior. These portholes were from five to six feet in diameter and were round. They also appeared to have a dark, circular, continuous window on the inside and bottom of their doughnut shape as though it were an observation window.
All of us aboard the boat were afraid this center balloon was going to crash in the bay, and just a little while before it stopped lowering, we had pulled our boat over to the beach and got out with our harbor patrol camera. I took three or four photographs of these balloons.
The center balloon-like aircraft remained stationary at about five hundred feet from the water while the other five aircraft kept circling over it. After about five or six minutes one of the aircraft from the circling formation left its place in the formation and lowered itself down right next to the stationary aircraft. In fact, it appeared to touch it and stayed stationary next to the center aircraft as if it were giving some kind of assistance for about three or four minutes.
It was then we heard a dull thud, like an underground explosion or a thud similar to a man stamping his heel on damp ground. Immediately following this sound the center aircraft began spewing forth what seemed like thousands of newspapers from somewhere on the inside of its center. These newspapers, which turned out to be a white type of very light metal, fluttered to earth, most of them lighting in the bay. Then it seemed to hail on us, in the bay and over the beach, black or darker type of metal which looked similar to lava rock. We did not know if this metal was coming from the aircraft but assumed it was, as it fell at the same time the white type metal was falling. However, since these fragments were of a darker color, we did not observe them until they started hitting the beach and the bay. All of these latter fragments seemed hot, almost molten. When they hit the bay, steam rose from the water.
We ran for shelter under a cliff on the beach and behind logs to protect ourselves from the falling debris. In spite of our protection, my sons arm was injured by one of the falling fragments and our dog was hit and killed. We buried the dog at sea on our return trip to Tacoma.
After this rain of metal seemed over, all of these strange aircraft lifted slowly and drifted out to the westward, which is out to sea. They rose and disappeared at a tremendous height. The center aircraft, which had spewed the debris, did not seem to be hindered in its flight and still remained in the center of the formation as they all rose and disappeared out to sea.
We tried to pick up several pieces of the metal or fragments and found them very hot -- in fact, I almost burned my fingers -- but after some of them had cooled we loaded a considerable number of the pieces aboard the boat. We also picked up some of the metal which had looked like falling newspapers.
My crew and I discussed this observance for awhile and I attempted to radio from my patrol boat back to my base. The static was so great it was impossible for me to reach my radio station. This I attributed to the presence of these aircraft, as my radio had been in perfect operating order and the weather would not have caused this amount of interference.
The wheelhouse on our boat had been hit by falling debris and damaged. We immediately started our engines and went directly to Tacoma, where my boy was given first aid at the hospital there. Upon reaching the dock I had to tell my superior officer how the boat had been damaged and why the dog had not returned with us. I related our experience to Fred L. Crisman, my superior officer. I could plainly see that he did not believe it and I guess I dont blame him, but we gave him the camera with its film and fragments of metal we had loaded aboard as proof of our story. Fred L. Crisman decided he would at least go and investigate the beach where I judged at least twenty tons of debris had fallen.
I might add that these strange aircraft appeared completely round, but seemed a little squashed on the top and on the bottom as if you placed a large board on an inner tube and squashed it slightly. The film from our camera, developed showed these strange aircraft, but the negatives were covered with spots similar to a negative that has been close to an X-ray room before it was exposed except that the spots printed white instead of black as in the usual case.
Enquête et explication officielle
Le FBI qui a immédiatement démarré une enquête suite au crash, entend Dahl et Crisman confesser qu'ils ont fabriqué cette histoire de soucoupe volante. les débris auraient consisté en des morceaux de ferraille et de pierre ponce récupéré sur la plage de Maury Island. L'Armée US et les survivants confirment que le crash du B-25 a été causé par un feu de moteur.
Dahl meurt le .