Cycling clubs, sportive organisers and triathlon: the wind call, at your height

As a club captain or event director, you make critical decisions for events. These include whether to proceed with the entire course, or specifically the sea-swim leg, on event day. This decision is made for each event you organise.

A wrong call can have significant consequences. For example, events have been cancelled due to adverse weather, leading to entry refunds. More critically, there have been instances where events have faced tragic outcomes related to water conditions, highlighting the importance of accurate wind information when assessing conditions for a sea-swim leg.

Your decision is guided by the wind conditions at your event site. The Wind Agent provides data at 10 metres, and interpolates to your working height, focusing on gust and direction. This information helps you assess the risk and make an informed decision for your participants.

Ultimately, the call to go ahead, modify the course, or cancel an event rests with you, the competent person on site, based on your own event rules and the real-time information available.

For cycling and triathlon events, understanding the wind at 10 metres is generally most relevant, particularly for exposed sections of a course or the sea-swim leg. The instrument shows wind at standard heights of 10, 80, 120, and 180 metres, and then interpolates to your specific working height in metres.

Your concern will often be with gusts rather than the mean wind speed. Gusts are short, sudden increases in wind speed and can pose a greater challenge to participants, especially in open water or on exposed cycling routes. The instrument displays gusts alongside the mean wind speed, allowing you to assess both.

Your event's operational document will specify the wind speed or gust limit at which you must consider altering or cancelling parts of your event. You input this limit into the instrument, which then highlights when forecast conditions approach or exceed it. This helps you to quickly identify potential issues.

Remember, your limit is set by your own document. The instrument does not set or recommend limits, but helps you monitor against the ones you have defined.

The instrument provides the P(above your limit) by the hour. This is the fraction of ensemble members, from the weather model, that predict wind conditions will exceed the limit you have set for your event. This percentage is computed from ensemble members at 10, 80, 100, and 120 metres.

When you see a P(above your limit) of, for example, 20 per cent, it means that two out of ten model runs predict conditions will exceed your limit. At this level, you might proceed with the sea-swim leg, but brief participants about the potential for challenging conditions on an exposed part of the course. You might also have contingency plans ready.

If the P(above your limit) rises to 50 per cent, five out of ten model runs show conditions above your limit. This would likely prompt a more serious discussion about altering the course or cancelling the sea-swim leg. You would be preparing to implement your alternative plans.

At 80 per cent P(above your limit), eight out of ten model runs indicate conditions above your limit. This would strongly suggest cancelling the sea-swim leg or the entire event, depending on your rules and the nature of the forecast. The Agreement Spine feature shows where different weather models align or diverge in their predictions, providing additional context for your decision.

Let's consider a typical event day using the instrument to inform your decisions.

At 06:00, you check the forecast. The P(above your limit) for the sea-swim leg, set at a gust limit of 15 knots, is 20 per cent for the 10:00 to 12:00 window. The Agreement Spine shows good model consensus, suggesting a low but present risk.

By 07:30, after consulting your event team, you decide to proceed with the sea-swim leg, but you issue a strong advisory to all participants about potentially choppy conditions. You also ensure extra water personnel are deployed.

At 09:00, with participants starting to gather, you re-check the forecast. The P(above your limit) has risen to 40 per cent for the critical hours. The Agreement Spine shows some models now predicting higher gusts. You decide to monitor closely.

At 10:30, as the first wave of swimmers enters the water, the observed gust at 10 metres reaches 14 knots. The instrument's record page automatically logs this observation against the forecast.

By 11:30, with all swimmers out of the water, the wind eases slightly, and the cycling leg proceeds as planned. The instrument's record page provides a full, dated account of the forecast, observed conditions, your chosen limit, and the decision you made.

Your event's operational document is the authoritative source for setting your wind limits. This document will specify the maximum gust speed or mean wind speed at which you must consider modifying or cancelling parts of your event, such as the sea-swim leg or exposed cycling sections.

You will input this specific limit into the instrument. For example, your document might state that the sea-swim leg cannot proceed if gusts at 10 metres are forecast to exceed a certain value. You would enter this value as your gust limit for the sea-swim leg.

The instrument is preset to 10 metres for your persona, which is a common height for assessing surface-level wind conditions relevant to these types of events. If your document specifies a different height, you can adjust your working height in metres accordingly.

It is crucial that the limit you use in the instrument directly reflects what is written in your own event's operational guidelines. The instrument does not provide a recommended limit; it simply helps you monitor conditions against the limits you have already established.

The instrument maintains a dated record page of what was forecast, what was observed, the limit you used, and the call you made. This record is vital for event directors and club captains.

After an event, especially if conditions were challenging or decisions were questioned, you may need to provide evidence for the actions taken. For instance, if you cancelled a sea-swim leg, stakeholders or participants might ask for justification. Your record page provides a clear, verifiable account.

This record serves several purposes:

• Accountability: It documents your decision-making process based on available wind data.
• Review: You can review past events to refine your operational procedures and limits for future events.
• Justification: It provides concrete data to support your decisions, such as altering a course or cancelling an event due to adverse wind conditions.

This immutable record is a key part of your event management, offering transparency and a factual basis for your operational choices. It allows you to demonstrate due diligence in assessing and responding to wind conditions, which is particularly important for participant well-being and event integrity.

Ireland's location on the Atlantic seaboard means that events, particularly between October and March, are frequently exposed to strong winds and changeable weather. While the main season for cycling sportives and triathlons typically runs from April to September, even during these months, sudden shifts in wind conditions are common.

Met Éireann provides national weather forecasts, but local conditions, especially on exposed coasts or mountainous routes, can differ significantly. For event directors, understanding these localised wind patterns is critical for participant well-being and event viability.

Past events in Ireland have faced cancellations due to adverse weather, including wind. These instances underscore the importance of precise, real-time wind data for making go/no-go decisions. The instrument helps you assess the risk specifically for your event location.

By focusing on gust speeds and the P(above your limit), you can better anticipate and respond to the specific challenges posed by Ireland's often dynamic wind environment, ensuring your event decisions are well-informed.