TORRUELLA, Chief Judge.

Plaintiff-appellant Joanne Joyce, individually and as executrix of the estate of her spouse, James Joyce, (the "Joyces") appeals the district court's grant of summary judgment to defendants, two police officers and the Town of Tewksbury, Massachusetts, on the issue of whether the entry of police officers into her home without a search warrant violated the Fourth Amendment. Appellant filed suit under 42 U.S.C. §(s) 1983, seeking damages arising out of the warrantless search. Because the officers entered the Joyces' home under exigent circumstances — in hot pursuit of the subject of an arrest warrant — we affirm the district court's grant of summary judgment, finding no Fourth Amendment violation.

BACKGROUND

In reviewing the district court's grant of summary judgment, we present the facts in the light most favorable to the nonmovant, here the Joyces. See, e.g., Woodman v. Haemonics Corp., 51 F.3d 1087, 1089 n. 1 (1st Cir. 1995). The following facts are undisputed.

Shortly after 11:15 p.m. on August 6, 1989, two police officers employed by the Town of Tewksbury, Alfred Donovan ("Donovan") and Robert Budryk ("Budryk") (together, "the officers"), were dispatched to the Joyces' single family residence on the basis of a tip that the Joyces' son, Lance Joyce ("Lance"), had violated a protective order and could be found at the Joyces' house. The officers were sent to the Joyces' house in order to arrest Lance. At the time, Lance was not regularly residing with the Joyces.

The officers approached the side door of the house, knocked on the door, and observed Lance inside. Lance opened the inside door. Through the closed storm door, the officers told Lance that they had a warrant for his arrest, to which Lance replied, "ya right." Budryk asked Lance to step outside. Lance retreated from the side door and went into the living room. Budryk then opened the outside storm door and the two officers entered the house, without seeking or receiving the consent of either Lance or the Joyces. Donovan then told Lance he was under arrest. The officers did not have a search warrant authorizing entry into the Joyces' residence.

After the officers followed Lance into his parents' house, Lance called for his mother and the Joyces came downstairs. Mr. Joyce was called to the kitchen by a third officer, Robert Westaway, who arrived after Budryk and Donovan. Westaway directed Mr. Joyce to the kitchen to speak on the telephone with an unidentified officer at the police station, who stated that the officers were acting pursuant to a warrant for Lance's arrest. After arguing with Mrs. Joyce, and after Mr. Joyce told Lance to go with the officers, the officers handcuffed and removed Lance from his parents' living room.

The Joyces brought suit in April 1990 in district court seeking compensatory and punitive damages, under 42 U.S.C. Section(s) 1983, arising from the warrantless search, as well as relief on various other causes of action. After denying a motion for summary judgment filed by the Joyces, the district court granted defendants-appellees' motion for summary judgment on the Fourth Amendment unreasonable search and seizure claim. The remaining claims were either withdrawn by plaintiffs prior to trial or tried in June 1995, with judgment for defendants.

Joanne Joyce appeals the grant of summary judgment for defendants on the Fourth Amendment search and seizure claim, and urges that a retrial be ordered on the other counts, on the ground that the district court's incorrect ruling as to the legality of the officers' search prejudiced the trial on their other claims. We thus focus our attention on the issue of unreasonable search and seizure under the Fourth Amendment.

STANDARD OF REVIEW

In the summary judgment context, we review the district court's grant of summary judgment de novo, and "are obliged to review the record in the light most favorable to the nonmoving party, and to draw all reasonable inferences in the nonmoving party's favor." LeBlanc v. Great American Ins. Co., 6 F.3d 836, 841 (1st Cir. 1993), cert. denied, ___ U.S ___, 114 S.Ct. 1398 (1994).

We will uphold summary judgment where "the pleadings, depositions, answers to interrogatories, and admissions on file, together with affidavits, if any, show that there is no genuine issue as to any material fact and that the moving party is entitled to judgment as a matter of law." Fed.R.Civ.P. 56(c).

DISCUSSION

I. Relevant Fourth Amendment Law

The warrantless, non-consensual search of a private residence is presumptively invalid under the Fourth Amendment. Payton v. New York, 445 U.S. 573, 586, 590 (1980) ("[T]he Fourth Amendment has drawn a firm line at the entrance to the house. Absent exigent circumstances, that threshold may not reasonably be crossed without a warrant."). To counter the presumption of invalidity, the government must show that its warrantless search falls within a recognized exception to the warrant requirement. See United States v. Doward, 41 F.3d 789, 791 (1st Cir. 1994), cert. denied, ___ U.S. ___, 115 S.Ct. 1716 (1995).

Exceptions to the search warrant requirement exist for certain "exigent circumstances," in which the "compelling necessity for immediate action" renders unacceptable the delay of obtaining a warrant. United States v. Adams, 621 F.2d 41, 44 (1st Cir. 1980); accord United States v. Tibolt, 72 F.3d 965, 969 (1st Cir. 1995), cert. denied, ___ U.S. ___, 116 S.Ct. 2554 (1995). Exigent circumstances justifying warrantless searches include: "'(1) 'hot pursuit' of a fleeing felon; (2) threatened destruction of evidence inside a residence before a warrant can be obtained; (3) a risk that the suspect may escape from the residence undetected; or (4) a threat, posed by a suspect, to the lives or safety of the public, the police officers, or to [an occupant].'" Tibolt, 72 F.3d at 969 (quoting Hegarty v. Somerset County, 53 F.3d 1367, 1374 (1st Cir. 1995), cert. denied, ___ U.S. ___, 116 S.Ct. 675 (1995)); see also Minnesota v. Olson, 495 U.S. 91, 100 (1990).

An arrest warrant does not, in and of itself, satisfy, or create an exception to, the Fourth Amendment's search warrant requirement with regard to the residences of persons not named in the arrest warrant. Steagald v. United States, 451 U.S. 204, 205-06, 213-14 (1981); see also United States v. Curzi, 867 F.2d 36, 39 (1st Cir. 1989) ("In Steagald, the Court ruled that obtaining an arrest warrant for A was not sufficient to authorize B's home to be entered and searched in the course of effecting A's apprehension."). Nevertheless, the hot pursuit exception may apply to instances in which police chase fugitives who are the subject of arrest warrants into someone else's residence.

The "hot pursuit" exception requires, at least, that there be "some sort of a chase" of the proper subject of an arrest. United States v. Santana, 427 U.S. 38, 43 (1975). In Santana, the Supreme Court established that for the purposes of satisfying the exigent circumstances exception, the "hot pursuit" need not be an extended chase. Id. Indeed, in Santana the Court held that merely following the suspect from the doorway into a house qualified as hot pursuit: "the fact that the pursuit here ended almost as soon as it began did not render it any the less a 'hot pursuit' sufficient to justify the warrantless entry." Id.

The facts of Santana are particularly relevant to the case at bar. Santana involved the arrest of a suspected felon who was standing at the doorway of her home, and who retreated into the vestibule of her house on seeing police officers approach. The Court found that the police, in hot pursuit, validly followed her into her home — without a search warrant — to complete the arrest. Id.

As a practical matter, the hot pursuit exception often serves to ensure that "a suspect may not defeat an arrest which has been set in motion in a public place . . . by the expedient of escaping to a private place." Id. The hot pursuit exception affords law enforcement officers the opportunity to complete an arrest already in progress by making warrantless entries to effectuate arrests. See, e.g., Harbin v. City of Alexandria, 712 F. Supp. 67, 71-72 (E.D. Va. 1989), aff'd, 908 F.2d 967 (4th Cir. 1990) ("[Santana] recognized that a defendant could not thwart an otherwise valid arrest by retreating from the doorway of her home into the vestibule of her house. The Santana principle has sensibly been extended to Terry stops.").

II. Application of Law

Exigency determinations are always highly fact-specific. See United States v. Lopez, 989 F.2d 24, 27 (1st Cir. 1993), cert. denied, 510 U.S. 872 (1993) ("There is considerable case law on exigent circumstances but, as one might expect in this area, the cases are heavily dependant on the facts."). We have never held, and do not hold now, that police pursuit of the subject of an arrest warrant automatically justifies the warrantless entry of private property. Rather, in determining whether police officers confront exigent circumstances — involving the "compelling necessity for immediate action," Adams 621 F.2d at 44 — we have assessed the totality of the objective facts reasonably known to, or discoverable by, the officers at the time of the search. See Tibolt, 72 F.3d at 969 (citing Illinois v. Rodriguez, 497 U.S. 177, 186 (1990)); Archibald v. Mosel, 677 F.2d 5 (1st Cir. 1982).

We find that the hot pursuit exception, particularly as it has been applied by the Supreme Court in Santana, applies in the instant case. Additionally, we note that a crucial factor in assessing the reasonable perception of exigent circumstances is whether the delay in obtaining a search warrant would pose a "threat to safety." See Lopez, 989 F.2d at 25 (collecting cases) ("[A] solid line of cases finds exigent circumstances where the safety of law enforcement officers or the general public is threatened."). The instant case raises both the important interest in completing the arrest of an individual suspected of a serious crime (hot pursuit) as well as the need to prevent both the suspect's escape and further harm.

A. Hot Pursuit

Officers Budryk and Donovan were acting on a tip that Lance would be at the Joyces' address. They began Lance's arrest in an area not implicated by the Fourth Amendment — outside of the Joyces' side doorway — by communicating with the arrestee at the threshold of the house. A person standing in the threshold of a dwelling, visible to the public, cannot claim a privacy interest protected by the Fourth Amendment. See Santana, 427 U.S. at 42. The initiation of Lance's arrest, therefore, does not raise Fourth Amendment concerns. The officers then followed the fleeing arrestee into the house to complete the arrest. These facts are very similar to those in the Santana case, in which the Supreme Court found that the hot pursuit/exigent circumstances exception to the warrant requirement applied.

In Santana the intended arrestee was standing in the doorway of her house holding what appeared to be illicit drugs. Id. at 40. The police drove up to within fifteen feet of her, got out of their van, and shouted "police." As the officers approached, Santana "retreated into the vestibule of her house." Id. Noting "the need to act quickly," the Court held that the police properly entered the house without a search warrant. Id. at 42-43. The key facts in the instant case are analogous: Lance retreated from the threshold of a private residence after it was clear that the police were making an arrest; the officers could reasonably conclude that they needed to act quickly to ensure that Lance did not escape or retaliate.

Appellant attempts to distinguish the instant case from Santana on a number of factual grounds, the cognizably principled distinctions being: that Lance, unlike Santana, was not engaged in a felony at the time he was arrested; that there was no risk that he would destroy critical evidence, whereas Santana was observed carrying illicit drugs; and that Lance did not retreat into his own house, whereas Santana did. A plain reading of the Supreme Court's opinion in Santana, however, suggests that none of these factual distinctions should halt us from applying its rule to the facts before us.

First, although Lance was not in the midst of engaging in a felony at the time he was apprehended, there was a warrant outstanding for his arrest on a serious crime, whereas there was no arrest warrant in Santana. Having no arrest warrant, the officers in Santana had to establish both probable cause for arrest in a public place as well as reasonable grounds for entry without a search warrant (hot pursuit). Id. The fact that Santana was observed in the course of engaging in a felony was relevant to the finding of probable cause for her arrest; the functional equivalent in the instant case is the arrest warrant for Lance. Once the Santana Court found that the police had established probable cause for arrest, it addressed the question of entry in hot pursuit. Id. at 42. In the Court's words, once it found probable cause for arresting Santana, the "remaining question [was] whether her act of retreating into her house could thwart an otherwise proper arrest." Id. The Santana Court framed the entry issue broadly — that is, not as applying only to felons, but instead as applying to any proper arrestee — and never suggested that the fact that Santana was engaged in a felony was a decisive factor in applying the hot pursuit doctrine. Id. at 42-43.

On the other hand, not all infractions of law may support warrantless searches on an exigency rationale. See Welsh v. Wisconsin, 466 U.S. 740 (1984) (no exigency where warrantless entry into home was for purpose of arrest on civil, nonjailable traffic offense). In Welsh, the Supreme Court held that "an important factor to be considered when determining whether any exigency exists is the gravity of the underlying offense for which the arrest is being made." 466 U.S. at 753. In holding that the exigent circumstances exception was inapplicable to the case before it, the Welsh Court found that the underlying offense was nonjailable under relevant state law, and also found that the government could not rely on a hot pursuit rationale, because "there was no immediate or continuous pursuit." Id. In the instant case, by contrast, Lance was suspected of a serious, jailable offense: the violation of a protective order is a criminal offense under the Massachusetts Abuse Prevention Act, punishable by fine or imprisonment of up to two and a half years, Mass. Gen. L. ch. 209A, Section(s) 7 (1992). It goes without saying that domestic violence and violations of protective orders are among the more grave offenses affecting our society; the seriousness of violating a protective order is reflected by the potential for substantial incarceration under Massachusetts law. Even if the crime underlying Lance's arrest warrant is not technically a felony under Massachusetts law, we find it to be a serious underlying crime that adequately contributes to the kind of exigency captured in the phrase "hot pursuit of a fleeing felon." Thus, in the instant case, Santana cannot be distinguished on the ground that the arrestee's underlying crime is not technically a felony.

Second, appellant points out that the Court in Santana explicitly stated that the officers could not afford delay for fear that evidence would be destroyed. Although this is true, in the instant case the officers could have had reasonable fears that are no less important than the fear that evidence may be destroyed, such as the fear that Lance himself would flee, or that he would get a weapon or in some other way prevent arrest. Santana does not stand for the proposition that fear of destruction of evidence is a necessary prerequisite for the hot pursuit exception. Rather, one can only reasonably infer that, by referring to one of the real costs of the delay that would result from obtaining a search warrant, the Santana Court was placing the hot pursuit exception within its context as an important, but not exclusive, ground for finding exigent circumstances. In the instant case, as discussed below, other risks and reasonable fears were at play.

Third, appellant claims that Santana is not controlling because Lance retreated into his parents' home, whereas Santana retreated into her own home. Nothing in the Court's opinion, however, suggests that its finding of hot pursuit hinged on Santana's retreat into her own home. Indeed, in a concluding paragraph, the Court spoke in broad terms of following a suspect into any private residence and not merely of entry into the residence of the arrestee:

We thus conclude that a suspect may not defeat an arrest which has been set in motion in a public place, and is therefore proper under [United States v. Watson, 423 U.S. 411 (1976)], by the expedient of escaping to a private place.

Id. at 43 (emphasis added).

Appellant further contends that reversal is required because the actions of the police officers did not constitute an arrest prior to their entry into the house. Appellant argues that the district court committed reversible error by finding that an arrest had been made prior to entry. We simply need not determine, however, whether an arrest had been completed prior to the officers' entry in order to find that the officers' entry satisfies the hot pursuit exception. All we need to find, to fall fully within the holding in Santana, is that an arrest was commenced in a place outside of the private zone protected by the Fourth Amendment. Here, appellant does not dispute that the officers told Lance they had a warrant for his arrest and asked him to step outside, before Lance retreated and the officers followed. Because undisputed facts show that Lance's arrest had been "set in motion" outside the Joyces' home, Santana applies, and we conclude that the officers responded reasonably to exigent circumstances by following the arrestee in hot pursuit into the Joyces' home.

B. Other Exigency Factors

A court making fact-intensive exigency determinations need not rest its conclusion on one factor alone. Although the hot pursuit rationale of Santana is the central factor in this case, its application is further justified in the instant circumstances by the legitimate concern of the arresting officers, based on Lance's immediate retreat, that he might escape. Among the well-established grounds for basing an exigency finding are: "a risk that the suspect may escape from the residence undetected." Tibolt, 72 F.d at 969 (quoting Hegarty, 53 F.3d at 1374). The officers may also have reasonably harbored some concern for their own safety; it is not inconceivable that a party charged with violating a protective order would use the seclusion of his parents' house as an opportunity to seek out a weapon for the purpose of resisting arrest. Fourth Amendment case law has established that threats to the safety of law enforcement officers are to be considered in the exigent circumstances calculus. Lopez, 989 F.2d at 25.

"The nature of the search is also important." Id. at 26. While Lance is not technically a "fleeing felon" under Massachusetts law, as discussed above, the totality of the facts in the instant case presents exigent circumstances adequate to justify this particular warrantless entry. See Lopez, 989 F.2d at 26 (explaining that when making exigency determinations, the question is whether the circumstances "justify a warrantless search of the kind that occurred.") (emphasis added). Intrusions into private homes require the most careful Fourth Amendment scrutiny. See, e.g., United States v. Rengifo, 858 F.2d 800, 805 (1st Cir. 1988), cert. denied, 490 U.S. 1023 (1989) (finding exigent circumstances justified warrantless search of motel room but noting that court may be "more critical" of police conduct when in private residence). Nevertheless, the officers did not search the Joyces' home in an overly intrusive manner. Rather, they followed Lance to complete the arrest and did not engage in any further searching. Nothing in the record suggests that the hot pursuit in this case served as a pretext to search for anyone or anything other than the arrestee.

III. Waiver of Arrest Warrant Challenge

Appellant calls into question the existence of the arrest warrant for Lance's arrest. The plaintiffs never squarely presented an argument to the district court, either in their summary judgment motions or in their complaint, that an arrest warrant for Lance was not outstanding. Because this argument was not presented before the district court, we need not consider it on appeal. Nat'l Ass'n of Social Workers v. Harwood, 69 F.3d 622, 627-29 (1st Cir. 1995). Although this waiver rule has its exceptions, these are allowed only in "horrendous cases" where a gross miscarriage of justice would result from waiver. See Credit Francais Int'l v. Bio-Vita, Ltd., 78 F.3d 698, 709 (1st Cir. 1996) (citing Johnston v. Holiday Inns, Inc., 595 F.2d 890, 894 (1st Cir. 1979)). The specter of gross miscarriage of justice plainly does not arise from our waiver of appellants' arrest warrant challenge. Even assuming that a proper arrest warrant did not exist, it is not disputed that the officers believed they were acting on a proper arrest warrant. As stated above, the Fourth Amendment inquiry at issue turns on the reasonable belief of the arresting officers. See Archibald, 677 F.2d at 7 (holding that police officers need not be factually correct in order to satisfy exigent circumstances exception, but must have had a "reasonable perception of exigent circumstances"), cited with approval in Rodriguez, 497 U.S. at 186.

CONCLUSION

For the reasons presented above, the district court's grant of summary judgment to defendants is affirmed. There is therefore no reason to disturb the verdicts on any other counts.