Lynn L. Rogers, et al., Respondents, vs. John Moore, et al., Appellants.

may not be cited except as provided by

Minn. Stat. § 480 A. 08, subd. 3 (1996).

 STATE OF MINNESOTA

 IN COURT OF APPEALS

 C3-97-1345

Wilfred Godbout, et al.,

Appellants,

vs.

City of Cloquet,

Defendant,

CJ's of Cloquet, Inc.,

Respondent.

 Filed February 10, 1998

 Reversed; motion to strike denied

 Klaphake, Judge

 Dissenting, Harten, Judge

Carlton County District Court

File No. C0-96-1320

Jeffrey A. Westermann, Newby, Lingren, Carlson & Skare, Ltd., 1219-14th Street, Cloquet, MN 55720 (for appellants)

Thomas R. Thibodeau, Jerome D. Feriancek, Johnson, Killen, Thibodeau & Seiler, P.A., 230 West Superior Street, Duluth, MN 55801 (for respondent CJ's of Cloquet)

Considered and decided by Klaphake, Presiding Judge, Huspeni, Judge, and Harten, Judge.

 U N P U B L I S H E D O P I N I O N

 KLAPHAKE, Judge

On December 23, 1994, between 9:30 and 10:00 a.m., appellant Wilfred Godbout slipped and fell on the public sidewalk outside the entrance to respondent CJ's of Cloquet, Inc. (CJ's). Godbout and his wife, LaVerna, brought this negligence action against CJ's and the City of Cloquet. The district court granted summary judgment to the city and CJ's, and dismissed the action. The Godbouts appeal the grant of summary judgment to CJ's.[1]

Because the Godbouts presented evidence suggesting that "black ice" had formed underneath the wet spots on the sidewalk and that the previous owner of CJ's property had had continual dripping problems caused by the roof overhang, the district court erred in concluding that, as a matter of law, CJ's owed no duty to the Godbouts. In addition, because the "mere slipperiness" doctrine applies only to municipalities, the district court erred in concluding that the Godbouts' claims against CJ's are barred by that doctrine. Finally, because fact issues exist as to whether Wilfred Godbout knowingly chose to encounter an avoidable hazard, the district court erred in concluding that primary assumption of the risk precluded the Godbouts from recovering against CJ's. We therefore reverse the district court's grant of summary judgment to CJ's.

 D E C I S I O N

Summary judgment is appropriate only if the record shows "that there is no genuine issue of material fact and that either party is entitled to a judgment as a matter of law." Minn. R. Civ. P. 56.03. On appeal, this court must "view the evidence in the light most favorable to the party against whom judgment was granted." Fabio v. Bellomo, 504 N.W.2d 758, 761 (Minn. 1993). Issues involving negligence are often fact-based and inappropriate for resolution on summary judgment. Block v. Target Stores, Inc., 458 N.W.2d 705, 712 (Minn. App. 1990), review denied (Minn. Sept. 28, 1990).

 I.

The district court concluded that CJ's owed no duty to the Godbouts because the danger was "open and obvious." A landowner is not liable to an entrant for physical harm caused by an "activity or condition on the land whose danger is known or obvious" to the entrant, "unless the [landowner] should anticipate the harm despite such knowledge or obviousness." Restatement (Second) of Torts § 343A(1) (1965) (adopted in Peterson v. W.T. Rawleigh Co., 274 Minn. 495, 497, 144 N.W.2d 555, 558 (1966)). Thus, a landowner has a continuing duty to protect an entrant "even for obvious dangers * * * if harm to an [entrant] should be anticipated despite the obviousness of the danger." Baber v. Dill, 531 N.W.2d 493, 496 (Minn. 1995); see  Adee v. Evanson, 281 N.W.2d 177, 178 (Minn. 1979). The test for obviousness is not whether the injured person actually saw the danger, but whether it was in fact visible. Munoz v. Applebaum's Food Market, Inc., 293 Minn. 433, 434, 196 N.W.2d 921, 922 (1972).

Here, although it is undisputed that wet spots were visible on the sidewalk, Godbout stated that he did not realize there was black ice under those wet spots until he was lying on the sidewalk after the fall. The danger here was not so obvious as to relieve CJ's of any duty: the danger was not clearly visible and was not commonly known or appreciated. See Baber, 531 N.W.2d at 496 (citing cases involving dangers so obvious that no warning necessary, such as low hanging branch, steep hill, large planter, lake, 20-foot square pool of water). Under these circumstances, we cannot conclude that, as a matter of law, the danger was open and obvious.

In addition, the record contains affidavits from the previous occupants of CJ's property, which state that they had continual problems with dripping from the roof overhang; that they would often go up on the roof and shovel off the snow to alleviate the problem; that the dripping occurred with such regularity that there were black spots on the sidewalk; that the dripping tended to create a light film of ice that was not readily apparent; and that they would salt and sand the sidewalk every morning because numerous people had fallen on the ice. Even though CJ's current owner claims that he was unaware of any problem, this evidence suggests that he should have known or anticipated the condition. Thus, for the purposes of summary judgment, the Godbouts have made a prima facie case that CJ's owed a duty to warn or guard against anticipated harm.

Finally, the record also reflects that this was not a sub-zero December day in northern Minnesota. Rather, the temperatures that day ranged between 38 and 10 degrees Fahrenheit. Under these circumstances, the jury could conclude that Godbout acted reasonably in assuming that he could safely traverse the edge of the wet spot and that he reasonably could not have anticipated or known about the black ice because of the mild conditions.

 II.

The trial court also concluded that the "mere slipperiness" doctrine barred the Godbouts' claims. However, that common law doctrine applies only to municipalities. A municipality may not be

held liable for injuries sustained in a fall on newly formed glare ice although a municipality is liable if it negligently permits an accumulation of ice and snow to remain on a sidewalk for such a period of time that slippery and dangerous ridges, hummocks, depressions, and other irregularities develop there.

 Doyle v. City of Roseville, 524 N.W.2d 461, 463 (Minn. 1994). We reject CJ's argument that when a city delegates responsibility to maintain sidewalks to an abutting landowner, the landowner becomes a "municipal agent" subject to the same protections as the city. The "mere slipperiness" doctrine recognizes that it is impossible for cities to guard against and remedy all defects. See id. (citing Henkes v. City of Minneapolis, 42 Minn. 530, 532, 44 N.W. 1026, 1027 (1890)). This purpose would not be served by extending the doctrine to private landowners.

 III.

The trial court further concluded that primary assumption of the risk barred the Godbouts' claims. The elements of primary assumption of the risk "are whether a person had (a) knowledge of the risk, (b) an appreciation of the risk, and (c) a choice to avoid the risk but voluntarily chose to chance the risk." Andren v. White-Rodgers Co., 465 N.W.2d 102, 104-05 (Minn. App. 1991), review denied (Minn. Mar. 27, 1991). For the defense to apply, Wilfred Godbout must have had actual knowledge of the danger; if it appears that he merely should or could have discovered the danger, the defense is contributory negligence and not assumption of the risk. Beckman v. V.J.M. Enters., Inc., 269 N.W.2d 37, 39 (Minn. 1978).

Although Godbout had actual knowledge of a wet spot on the sidewalk and had an opportunity to avoid the wet spot by walking around it, we cannot conclude that he had actual knowledge of the black ice underneath the wet spot. The district court therefore erred in concluding that primary assumption of the risk barred the Godbouts' claims.

 IV.

Finally, CJ's moves to strike a document contained in appellant's appendix because it was first submitted at the summary judgment motion hearing and was not filed with the district court. The document is clearly relevant: it is entitled "Climatological Observations" and contains the Cloquet Forestry Center records of daily temperature for December 1994. In addition, CJ's waived any objection it might now have to the document's late submission because its attorney agreed at the summary judgment hearing to accept the figures provided. We therefore deny CJ's motion to strike.

The district court's grant of summary judgment to CJ's is reversed.

  Reversed; motion to strike portion of appellants' appendix denied.

 HARTEN, Judge (dissenting).

Because the district court properly ruled that CJ's did not have a duty to Godbout in the circumstances, I respectfully dissent.

The supreme court has expressly approved Restatement (Second) of Torts § 343A(1) (1965). Peterson v. W.T. Rawleigh Co., 274 Minn. 495, 497, 144 N.W.2d 555, 557 (1966). Section 343A(1) provides:

A possessor of land is not liable to his invitees for physical harm caused to them by an activity or condition on the land whose danger is known or obvious to them, unless the possessor should anticipate the harm despite such knowledge or obviousness.

(Emphasis added.) The supreme court has reaffirmed the importance of the "unless" language. Adee v. Evanson, 281 N.W.2d 177, 178-79 (Minn. 1979). The parties here agree that under this rule a landowner has a continuing duty to protect an entrant "even for obvious dangers * * * if harm to an invitee should be anticipated despite the obviousness of the danger." Baber v. Dill, 531 N.W.2d 493, 496 (Minn. 1995).

The analysis, however, goes one step further. "A possesser of land * * * has no duty to an invitee where the anticipated harm involves dangers so obvious that no warning is necessary." Id. "The rationale underlying this rule is that `no one needs notice of what he knows or reasonably may be expected to know.'" Id. (quoting Sowles v. Urschel Lab., Inc., 595 F.2d 1361, 1365 (8th Cir. 1979)). The distinction between open and obvious dangers for which CJ's should anticipate harm and those for which it "should not anticipate harm because they are so open and obvious is a fine one," but one the court must make. Id. The test for obviousness is "not whether the injured party actually saw the danger, but whether it was in fact visible." Munoz v. Applebaum's Food Market, Inc., 293 Minn. 433, 434, 196 N.W.2d 921, 922 (1972).

It is undisputed that the wet spots were visible on the sidewalk. It was December 23 in Minnesota which, in itself, makes it quite obvious that sidewalks may be dangerous. The obviousness of that danger is increased by the fact that the sidewalk was not completely clear of water. It may reasonably be expected that residents of Minnesota know of these dangers. The district court properly concluded that CJ's did not have a duty to warn. I would affirm.

[ ]1 The Godbouts do not challenge the dismissal of the city, nor has the city participated in this appeal.