Warning is a key task for any intelligence service, but this task has become more demanding than ever before. The threats one faces today are often subtle and challenging to reveal before they turn into serious problems. One important method used by Western intelligence services since the Cold War is indicator-based alert analysis. Even though this method was developed in the context of a relatively static threat, to warn decision-makers about a possible Soviet attack, indicator-based analysis is still useful in the face of today’s more subtle threat environment. However, the method can and is being further developed to help analysts discover hybrid threats.