Ski Safety Expert Fails to Employ Experienced-Based Methodology Properly
Posted on March 26, 2025 by Expert Witness Profiler
On March 19, 2023, a ski collision at Aspen Highlands Ski Resort between Tasha Barber (Plaintiff) and Christine Mack (Defendant) led to a lawsuit. Barber claims Mack, skiing uphill, had the responsibility to avoid the collision and is seeking damages for her resulting injuries. Mack denies these claims and has engaged Jonathan Delk as an expert witness. Delk’s expert report includes a section titled “Conclusion and Opinions” where he presents factual conclusions and his professional opinions. At the end of that section, Delk offered three opinions:
1. Barber was responsible for avoiding the collision based on her being the uphill skier.
2. Barber was neither prepared nor aware enough to begin skiing, nor does she acknowledge that her being in motion (“coasting”) as skiing, which it is. These real facts and perspectives shared by Tasha Barber prove that Tasha was not sufficiently in control or aware of her surroundings to have avoided a collision.
3. Barber’s choice of actions to avoid the collision (shouting, leaning back, twisting) were ultimately the cause of her skis coming into contact with Christine Mack’s. Tasha Barber’s movements were the ultimate mechanism of her injury.
The Plaintiff contested the admissibility of these opinions, asserting that they constituted paid advocacy rather than genuine expert testimony. Due to the absence of a reliable methodology supporting them, the Court deemed the opinions inadmissible. This motion, requesting the Court to reconsider its decision, was submitted approximately two weeks thereafter.

Ski Safety Expert Witness
Jonathan Delk is an experienced trainer and risk manager with 15 years of ski, snowboard, and cycling coaching and training experience. From 2004 – 2019 he was employed in various roles in the ski industry including instructor,
guide, coach, trainer, manager, and director of snowsports.
During his tenure in the ski industry, he created and administered safety trainings for instructors and resort staff related to the Skier’s Responsibility Code and the Colorado Skier’s Safety Act. While his primary work has shifted fields, he remains active in the ski industry both as an instructor and member of PSIA-AASI, the governing body of instructor certifications in the United States for which he was also employed during his career as an examiner.
Discussion by the Court
The Federal Rules of Civil Procedure do not expressly provide for a motion for reconsideration on non-dispositive issues. But district courts have plenary power to revisit and amend interlocutory orders as justice requires. When asked to amend such an order, “courts consider whether new evidence or legal authority has emerged or whether the prior ruling was clearly in error.”
The Court determined that the Defendant misunderstood the applicable standard, instead arguing for the application of state reconsideration rules. Consequently, because the Defendant relied on the incorrect standard, she failed to address the proper one. Furthermore, she criticized Magistrate Judge Chung’s analysis of Delk’s opinions, thereby attempting to reargue her previous points. Ultimately, however, the Tenth Circuit had clearly stated that a motion for reconsideration was not meant for relitigating previously decided issues by the losing party.
To illustrate, the Defendant made two additional attempts to justify Delk’s first opinion.
First Opinion
Firstly, she tried to strengthen the opinion by claiming personal experience with the crash site supported it. However, as the Court previously noted, this justification originated solely from the arguments of her counsel and was absent from Delk’s report.
If the Defendant wished to leverage Delk’s specific expertise regarding fall lines, she could have obtained a narrower opinion concerning how the various slopes and paths would generally impact a skier’s acceleration. She did not do so. Instead, she presented an opinion that relied on assumptions and presumptions to reach a broader conclusion on liability. This opinion exceeded the bounds of expertise by selecting facts for the jury and was therefore inadmissible.
The previous ruling specifically noted that the problem with the opinion is that it did not “explain how [his] experience leads to the conclusion reached, why that experience is a sufficient basis for the opinion, and how that experience is reliably applied to the facts.”
Second Opinion
The Court also found a similar flaw in the second opinion. The Defendant argued that Delk’s knowledge of ski equipment and its effect on reaction time would be helpful to a jury. While this might be accurate, it wasn’t the content of Delk’s report. Instead, the opinion merely criticized the Plaintiff’s preparedness by noting she was “possibly buckling her boots while in motion.” Thus, the core of the opinion didn’t rely on Delk’s expertise in ski equipment. Rather, it stemmed from Delk’s interpretation of the Plaintiff’s deposition testimony as to whether her conduct constitutes “paying attention to her direction of travel.” Jurors don’t need expert assistance to understand the meaning of paying attention.
Third Opinion
Lastly, the Defendant tried to justify Delk’s third opinion, arguing that his expertise in ski control supported his conclusions that the Plaintiff was (1) not buckling her boots, (2) looking down, (3) following the cues of another, and (4) not paying attention to her surroundings. However, the report lacked any explanation of a reliable methodology, based on training and experience, used to reach these conclusions. Furthermore, it’s unlikely a jury needs expert help to determine if the Plaintiff was buckling her boots in motion, looking down, or not just paying attention to her surroundings– or if such inattentive actions could cause an ensuing collision. The Court found that Delk’s opinion here didn’t help the jury understand the facts but rather directed them to choose a specific narrative, offering only an obvious consequence of that narrative as expertise.
Furthermore, the Defendant did not address Delk’s lack of qualifications to state that “Tasha Barber’s movements were the ultimate mechanism of her injury,” a “medical conclusion” for which “Delk has” no “medical training, education, or experience that would allow him to render an expert opinion on injury causation.” In essence, the Court did not disregard Delk’s experience or demand a scientific basis, but rather emphasized that “[e]xpert testimony based on experience alone must reveal how the experience led to the expert’s conclusion, why the experience is a ‘sufficient basis for the opinion,’ and how the experience was reliably applied.” Applying this standard, Delk’s report was deficient. The Defendant’s motion provides no evidence that striking Delk’s report was a clear error.
To the extent the Defendant desires to offer information about the Skier’s Responsibility Code, the Colorado Skier’s Safety Act, or other general skiing information to the jury, the previous order did not foreclose those possibilities.
Held
The Court denied the Defendant Christine Mack’s motion to
reconsider pursuant to C.R.C.P. 121 § 1-15(11) regarding Plaintiff’s 702 motion to strike Jonathan Delk’s opinions.
Key Takeaway:
While the Defendant correctly points out that excluding expert testimony should be the unusual case, a district court bears the responsibility of ensuring that such testimony is reliable, relevant, and helpful to the jury. Although Delk possesses knowledge regarding skiers’ responsibilities, the opinions the Defendant intends to present through him are not aimed at informing the jury about these duties. Rather, they seek to convince the jury, faced with different accounts of events, to adopt the version where the Plaintiff failed to meet those responsibilities.
Please refer to the blog previously published about this case:
Ski Safety Expert Witness is Not Qualified to Opine on the Ultimate Mechanism of Injury
Case Details:
Case Caption: | Barber V. Mack |
Docket Number: | 1:24cv260 |
Court: | United States District Court for the District of Colorado |
Order Date: | March 24, 2025 |