HOLLOWAY, Circuit Judge.

Mr. Unser brings this timely, direct appeal from his conviction for unlawful

possession and operation of a motor vehicle within a National Forest Wilderness Area in violation of 16 U.S.C. § 551 and 36 C.F.R. § 261.16(a). The maximum penalty for this conduct is a sentence of up to six months of imprisonment, a fine of up to $5,000, or both.

16 U.S.C. § 551 (setting out length of imprisonment authorized and maximum fine of $500);

18 U.S.C. § 3571(b)(6) (raising maximum fine to $5,000). The crime charged is a Class B misdemeanor (because the maximum authorized punishment is more than thirty days but no more than six months, 18 U.S.C. § 3559(a)(7)) and a “petty offense,” a category which includes misdemeanors of Classes B and C, plus “infractions,” 18 U.S.C. § 19.1 After a two-day trial to the court, Unser was convicted and was sentenced to pay a fine of $75.

This case arises from a story of survival in the wilderness under extreme conditions and involves legal issues requiring examination of some of the most fundamental concepts in criminal law. Like the parties obviously do, we view the case as having significance beyond the penalty actually imposed.

I

A

We will begin with an overview of the facts. Our summary in this part of the opinion is based on the testimony of the defendant, who was the only witness at trial to have been present during the primary events. Much of this evidence was undisputed; we will note later in the opinion the critical areas which are in dispute.

On Friday, December 20, 1996, Mr. Unser set off to go snowmobiling with a friend, Robert Gayton. Unser, who lives in Albuquerque and has a ranch near Chama in far northern

New Mexico, was very experienced with snowmobiles and fairly familiar with the place he chose for them to ride. Gayton had never been on a snowmobile before, and so took a few minutes to practice on the snowmobile at Unser’s ranch. The two then loaded two snowmobiles onto a trailer and made a short drive on state highways across the state line into far southern Colorado, high in the San Juan Range of the Rocky Mountains near La Manga

Pass.

They parked at the Red Lake Trail parking lot on state highway 17. From there, Unser planned a fairly short ride to the Jarosa Peak area of the Rio Grande National Forest. Unser planned on a fairly short ride for several reasons. It was already midday when they reached

the parking lot to begin riding, and of course nightfall would come early at that time of the year. While Unser was a very experienced rider, he had only recently recovered from back surgery, and his companion, as we have noted, was a beginner.

Gayton rode around a few minutes in the immediate area of the parking lot to get more

familiar with the machine and to riding in the deeper snow at the higher elevation near the pass. The two then set off for the Jarosa Peak area. The area around this peak includes a mesa, sometimes referred to as Jarosa Mesa, which was a climb of a few hundred feet from the parking lot. Unser said he chose this place because it was a fairly short and easy, yet interesting, ride for the beginner, Gayton.

The weather was clear at first, but when the two men reached the mesa, Unser testified, a “ground blizzard” came up rather suddenly. A ground blizzard was described as the result of high winds blowing substantial amounts of fallen snow; these conditions may arise when no new snow is falling. Visibility was near zero. Unser’s machine started having problems (the engine died repeatedly for the rest of the ill fated ride), and the situation

became dangerous. The two men got lost trying to find their way back to the truck. Then, Gayton went off into a small ravine and his machine was stuck. They abandoned it and rode on. As they did, they were continually having to work on Unser’s machine to get it restarted.

Eventually, it failed completely. The men started walking but were still lost when night came. They dug a snow cave and spent the night in it. The next day they continued their wanderings on foot, suffering greatly. They hiked through the day and night until some time after midnight when they came upon a barn equipped with a telephone. They were soon rescued. They were treated at a local hospital for frostbite, dehydration and exhaustion.

B

We will now review other evidence presented at trial. While Mr. Unser and Mr. Gayton were lost in the rugged terrain of the National Forest battling the extreme cold and other adverse elements, friends and family were aware that they had not returned on

Friday evening. On Saturday December 21 a search and rescue operation was organized.

Some friends of Unser went up from Chama to the parking lot where his truck had been noticed. On arriving there, they were told by a local deputy sheriff that they would have to wait for the authorized search and rescue team from Colorado to arrive, which they did.

Eventually, six to eight people went out from the trail head on snowmobiles looking for Unser and Gayton. The rescuers did not actually get out on the mountain until mid-afternoon, and so had only a couple of hours before nightfall. In that time they found the snowmobile that Gayton had been riding, but were unable to find enough tracks to determine which way the two men had gone from there.

At trial four witnesses who had participated in the search and rescue operation

testified. Only one of these witnesses, Richard Martin, was called by the government. Martin is a resident of southern Colorado and a veteran of a number of similar rescue efforts. Martin testified that the conditions were not bad on December 21 as the group began their search.

The men were able to find tracks and, at least at first, to follow the path that Unser and Gayton had made the previous day. From the tracks, it appeared that Unser had started out from the parking lot on a fairly well defined trail, one which had in years past been used by cattlemen taking stock up to summer pastures. (We note at this point that all the witnesses at trial agreed that Unser’s ill fated ride had begun along this route, but opinions were divided on where he might have gone after the first five or six miles.) That trail led up to what the witnesses referred to as Jarosa Mesa (but it is not clear from the record just how far this area goes). Conditions up on the mesa were very bad, as visibility was greatly reduced by blowing snow.

Martin testified that he found tracks on the mesa which appeared to have been made when Unser and Gayton were merely riding for fun; at the judge’s suggestion, he marked

“PT” on the enlarged map exhibit to show the area where he had found these “play tracks.”

The rescuers attempted to follow Unser’s tracks from there, but tracking became very difficult because so many of the tracks had been erased by blowing snow by that time.

Eventually, Martin found the snowmobile that Gayton had been riding. Martin testified that the tracks he had been following just before he found this first snowmobile indicated to him

that the riders were lost and trying to find their way. The rescue team extricated the abandoned snow mobile and rode on, dividing into two groups. At nightfall, they suspended their efforts for the day.

Martin marked on the map for the court the point where he estimated that the first snow mobile had been found and made a line to show the route he believed he had taken to this point. The route as drawn by Martin proceeds for slightly over three miles in a northwesterly direction, almost in a straight line from the point where Martin had marked

“play tracks” on the map, and ends about two miles past the boundary of the wilderness area.

This testimony was later cited by the trial judge as the most credible and consistent evidence as to the location of the first machine, an issue of fact which was of considerable significance because of other findings by the judge, as we shall see.

It is worth noting that Martin’s testimony was far from precise. Martin was candid in describing his effort as being less than certain, twice describing it as a guess. When the rescuers split into groups after having found the first abandoned snowmobile, Martin had ridden to Red Lake, which was northeast of the point he marked on the map as the likely

location of the first machine. Martin testified that his estimate of the location of the snowmobile was based in part on his belief that he had been going northeast from that point to Red Lake during the rescue efforts.

Martin had gone back to the area only a few days before trial in the company of Forest

Service Agent Burd, among others, to see if he could retrace the path he had taken during the rescue effort. Martin testified that they were very careful to stay out of the Wilderness Area and stopped before reaching the place where Martin believed the first snow mobile had been found. (Although it was June when this effort was made, they were on snowmobiles.) As the defense has emphasized, both at trial and on appeal, Martin said that the odometer on his snowmobile read 7.2 miles when he turned back at a point he (or others with him) estimated to have been about a quarter of a mile short of the wilderness boundary.2 Martin also testified that during this second visit to the area he tested his sense of direction and found that he was off by eighty degrees. He was not asked to explain whether he had accounted for this when he testified that he believed that the first snowmobile had been found southwest of Red

Lake.

It is interesting to note that on this second visit to the area, Mr. Martin had the 2 advantage of much better weather conditions and the assistance of maps and guidance from the Forest Service. Even so, he was uncertain just where the wilderness boundary was and said that he had never seen signs in this area marking the boundary.

C

About three weeks after this adventure, Unser contacted officials with the Forest

Service’s office in Albuquerque for assistance in finding the second snowmobile. Unser met with Ben Tafoya, a Forest Service Agent, on January 7, 1997, in Albuquerque. Because he had been told that he might need a permit to retrieve the machine, Unser brought with him a friend, Gabe Valdez, and Manny Martinez. Before retiring, Manny Martinez had been a supervisor in the law enforcement unit of the Forest Service and indeed had formerly been

Tafoya’s immediate supervisor. These men met and went over maps trying to determine where the machine might have been abandoned, but they believed that they had accomplished little. Further efforts were planned for the next day.

Tafoya told Unser that he would contact officials with the Colorado offices of the Forest Service who would be more familiar with the area and of more assistance. When

Tafoya first contacted officials in Colorado, he asked to speak to Chris Ortiz, the law enforcement officer for that area. Ortiz told Tafoya that he should speak with Brenda Schultz or Charlie Burd, who were investigating the incident for possible violation of the ban on use of motor vehicles in a wilderness area, having determined that Unser probably had entered

the South San Juan Wilderness Area of the Rio Grande National Forest. Those two agents, Burd and Schultz, arranged to come to meet with Unser at Tafoya’s office the following day.

Tafoya was asked not to tell Unser that these officers wanted to talk to him as part of their criminal investigation. Instead, Tafoya merely told Unser that two agents were coming down from Colorado who could help him locate and retrieve his snowmobile.

Charlie Burd, special agent with the Forest Service, testified that he, along with

Brenda Schultz, met with Unser the next day for about three and a half hours in a conference room near Tafoya’s office in Albuquerque. Unser came by himself to this meeting. Burd indicated that Unser was mostly cooperative during this meeting, but Burd suggested that

Unser was less than candid at times in saying that he had no idea which way he had gone after leaving Jarosa Mesa. After lengthy and not very productive discussions, Burd asked

Unser to draw a sketch of the valley where the second machine had been abandoned. From this sketch, Burd testified he was able to recognize the area. Burd then showed Unser an aerial phoptograph, using a stereoscopic device to give the photo a three dimensional effect.

Unser immediately recognized the photograph Burd had selected. Six months later, just the week before trial, Burd located the second machine, still stuck in the snow, very near the place that he and Unser had identified in the January meeting. Burd marked that point on the topographical map that Martinez had used in his testimony, government’s exhibit 3. The point is almost due east of the point identified by Martinez as the most likely location of the recovery of the first machine.

Burd testified that Unser never indicated to him that he had any concern for his safety until the second snowmobile failed. Unser had said that he had been in this area about ten times before, but that he was unsure just where they had gone because he simply had not been paying attention while he was enjoying the sport. According to Burd’s testimony, Unser told him that after the first machine got stuck, with the weather beginning to be bad, Unser decided to try to head straight back to the parking lot, rather than to return by retracing their path. Unser had told Tafoya that at that point he started following the “windrows.”

Windrows are wave like patterns in the snow which, Tafoya testified, would generally run east to west in this area.

D

As for the defense evidence, for purposes of our review we need not go into any detail. The trial judge clearly did not find much of the defendant’s evidence on critical issues to be credible. It is sufficient to note that two members of the rescue team attempted to

locate on the map the point where they thought the first snowmobile had been recovered, and like defendant in his testimony, both fixed this point as being outside the wilderness area, before Unser and Gayton would have reached the wilderness boundary. Matthew Martinez testified that he was among those who went back to the area on Sunday, December 22, after

Unser and Gayton had been rescued, to retrieve the first snowmobile. He said that the snowmobile’s odometer showed eight miles plus some tenths. Several witnesses agreed that a snowmobile’s odometer usually shows more miles than has actually been traveled. This is because the odometer registers revolutions of the track, which often slips especially when the rider is attempting to climb a steep slope. Mr. Burd testified that the route apparently taken by Unser up to the top of Jarosa Mesa was so steep that when he made the climb himself he thought at first that his machine would not be able to do it.

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II

On appeal from a criminal conviction, of course, we view the evidence in the light most favorable to the prosecution. In the instant case, where the trial judge found the facts specially, even though not requested to do so,3 the findings may not be disturbed unless clearly erroneous. Campbell v. United States, 373 U.S. 487, 493 (1963).

We will summarize the district judge’s findings as a prelude to our analysis of the legal issues raised by Mr. Unser. Although there is essentially no dispute as to the main events as described by Unser and as we have just summarized, there certainly was dispute

about important details. The trial judge did not credit Unser’s testimony in its entirety. In particular, the judge found that the two riders left the Jarosa Peak area before any emergency arose and that they were intentionally riding northwest, further away from where they had begun their ride, because they were still just riding for fun.

The judge found that Mr. Martin’s testimony as to the location of the first snowmobile was the most credible, and he gave several reasons for this finding. The fact that the second machine was eventually recovered almost due east from where Mr. Martin fixed the location of the first machine was consistent with the Unser’s statements, both in the interview with

Burd and in his trial testimony, that after abandoning the first machine he and Gayton

In the trial of a criminal case without a jury, the judge must make a general finding 3 and “shall in addition, on request before the general finding, find the facts specially.” Fed. R. Crim. P. 23(c). The findings may be oral or may be stated in an opinion or memorandum of decision. - 11 - attempted to follow the windrows, which the evidence established ran west to east. The judge found that the odometer reading on the first machine, when it was recovered, was a little over eight miles. The judge then said that he had used a piece of wire to determine the distance to the spot on the map marked by Mr. Martin, following the route Martin had said that rescuers had used in following the tracks left by Unser and Gayton. From this examination of the evidence, the judge determined that it was about 4.2 miles from the parking lot to the place which Martin had estimated to be the location of the abandoned first snowmobile. (In fact, the judge misread the scale of the map; the distance is twice what he found it to be. This is clear because he made findings about other points on the map, each of which is plainly based on the same erroneous reading of the scale of miles.) The judge then proceeded to consider Unser’s contention that if he had entered the wilderness area with a snowmobile, he had done so only under a life-threatening emergency. The judge had held before trial that Unser would have the burden of proving this defense by a preponderance of the evidence. This conclusion was based on another holding made before trial, i.e., that the offense charged was a strict liability offense and accordingly the government would not have to prove any intent to snowmobile in the wilderness area, nor would the government have to prove that Unser knew that he had entered a wilderness area. The judge stated, “[T]he law ought to afford, and I believe does, a measure of defense to the citation issued here based upon emergency and defenses otherwise known essentially as a necessity defense, sometimes called a choice of evils defense.” II App. at 687. - 12 - Accordingly, in the judge’s view it was critical to determine whether emergency conditions had arisen before or after Unser had entered the wilderness area. The judge specifically found that an emergency did not arise until “either just before or just after Mr. Gayton’s machine got stuck.” II App. at 689. Based on his finding that the more credible evidence was that the first machine had been found inside the wilderness boundary, the judge concluded and held that the defense had failed to carry the burden of establishing the necessity defense, and pronounced the defendant guilty. This appeal followed. The major contentions of defendant Unser on appeal are: (1) the district judge erred by holding that the offense of violation of 16 U.S.C. § 551 and 36 C.F.R. § 261.16(a) of possessing and using a motor vehicle in a Wilderness Area contains no mens rea requirement; (2) the judge erred by denying defendant Unser the necessity defense in the emergency conditions that confronted Unser and his companion; and (3) the judge erred in denying defendant Unser’s motion to suppress his statement based on the involuntariness of the statement and violation of his rights under the Miranda doctrine. We will analyze these issues in turn. III First, we address the mens rea issue: “Few areas of criminal law pose more difficulty than the proper definition of the mens rea required for any particular crime.” United States v. Bailey, 444 U.S. 394, 403 (1980). Our task is to determine, as best we can, the intent of Congress in empowering the - 13 - Secretary of Agriculture to adopt regulations applicable to National Forest lands and enforceable by criminal penalties. Then, having found that intent, we must determine whether the intent is compatible with due process. Unfortunately, we find little direct guidance in the language Congress used.^[4] The regulation promulgated by the Secretary of Agriculture likewise reveals little on this question.^[5] However, while the statute and regulation involved here do not contain a mens rea element, “silence on this point by itself does not necessarily suggest that the [legislators] intended to dispense with a conventional 16 U.S.C. § 551 provides, in pertinent part: