Multi-Factor Alerts for indicators with multiple timeframes is relatively straightforward.
TrendSpider uses the last calculated data point on the larger time frame for the alert.
For example, when you create an alert for a SMA crossover, such as the 15-min SMA 5 and the 1-hour SMA 15. The alert will go off when the SMA 15 crosses the last know data point for the 1-hour SMA 15.
Note: This may cause some issues when adding multiple conditions on smaller time frames alongside extremely large ones. For example, the alert below fires when the 5-min Stochastic K has crossed above the 5-min Stochastic D. In addition, the 5-min Stochastic D needs to be less than 20 and the 1-hour SMA 5 needs to greater then the 1-hour SMA 15. The alert in this picture appears to have misfired, but upon closer inspection, the algorithm works.
The alert correctly because it used an old data point from the 1-hour SMA 15 and 1-hour SMA 5. At the time the alert went off, the SMA 5 was greater then the SMA 15. Upon the closing of the 1-hour candle, the condition became untrue, which led to the apparent miss fire of the alert. This issue does not happen very often, but it is something to be aware of when creating these types of alerts.